Hypoglycaemic activity of four plant extracts traditionally used in South Africa for diabetes

Aim

To validate plant species for hypoglycaemic activity.

Materials and methods

Four plants were investigated for hypoglycaemic activity by evaluating inhibiting effects on carbohydrate-hydrolising enzymes: α-glucosidase and α-amylase. Acetone plant extracts were screened against C2C12 myocytes, 3T3-L1 preadipocytes and Chang liver cells by measuring glucose uptake. Cytotoxicity was done in preadipocytes and hepatocytes.

Results

Extract of Euclea undulata rootbark exhibited highest activity, displaying a glucose uptake of 162.2% by Chang liver cells at 50 μg/ml. An inhibition concentration of 50% for Euclea undulata was found to be 49.95 μg/ml for α-glucosidase and 2.8 μg/ml for α-amylase. No cytotoxicity was recorded for Euclea undulata, while Schkuhria pinnata and Elaeodendron transvaalense exhibited cytotoxicity at 12.5 μg/ml. α-Glucosidase and α-amylase assays showed inhibitory activity on enzymes for three plant extracts.

Conclusion

Euclea undulata, Schkuhria pinnata and Elaeodendron transvaalense showed in vitro hypoglycaemic activity. Schkuhria pinnata and Elaeodendron transvaalense indicated cytotoxicity on 3T3-L1 preadipocytes and Chang liver cells. Euclea undulata, Pteronia divaricata and Elaeodendron transvaalense inhibited α-glucosidase and α-amylase enzymes.

Ethnopharmacological relevance

Screening of plant extracts scientifically validated traditional use of Euclea undulata for treatment of diabetes. Cytotoxicity results revealed that acetone extracts of Schkuhria pinnata and Elaeodendron transvaalense are toxic and raise concern for chronic use.     

Investigating wound healing, tyrosinase inhibitory and antioxidant activities of the ethanol extracts of Salvia cryptantha and Salvia cyanescens using in vivo and in vitro experimental models

Ethnopharmacological Relevance

Salvia L. species are widely used against wounds and skin infections in Turkish folk medicine.

Aim of the study

The aim of the present study is to evaluate wound healing activity of the ethanol (EtOH) extracts of Salvia cryptantha and Salvia cyanescens.

Materials and methods

For the assessment of wound healing activity linear incision and circular excision wound models were employed on rats and mice. The wound healing effect was comparatively evaluated with the standard skin ointment Madecassol^®. Inhibition of tyrosinase, a key enzyme in skin aging, was achieved using ELISA microplate reader. Antioxidant activity was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide radical scavenger effect, ferrous ion-chelating ability, and ferric-reducing antioxidant power (FRAP) tests.

Results and Conclusions

The EtOH extract of Salvia cryptantha treated groups of animals showed 56.5% contraction, whereas the reference drug Madecassol^® showed 100% contraction. On the other hand, the same extract on linear incision wound model demonstrated a significant increase (33.2%) in wound tensile strength as compared to other groups. The results of histopathological examination maintained the upshot of linear incision and circular excision wound models as well.These findings specify that Salvia cryptantha for wound healing activity can be appealed further phytochemical estimation for spotting its active components.     

Analgesic and anti-inflammatory effects of Cassia siamea Lam. stem bark extracts

Aim of the study

The present study was carried out to investigate analgesic and anti-inflammatory activities of Cassia siamea Lam stem bark extracts. We have also determined the cytotoxicity of each extract.

Materials and methods

C. siamea, a widespread medicinal plant traditionally used in sub-Saharan Africa, was collected in Congo Brazzaville. Stem bark was extracted with petroleum ether (CSE1), chloroform (CSE2), ethanol (CSE3) and water (CSE4). Analgesic, anti-inflammatory and antipyretic activities of these extracts were assessed in rats with hot plate test, paw pressure and carrageenan induced paw oedema. Cytotoxicity was assessed against KB and Vero cells.

Results

At the doses used (100, 200, and 400 mg/kg) ethanol and water extracts showed significant and dose-dependent analgesic and anti-inflammatory effects. None of the extracts had cytotoxic activity on KB and Vero cell lines and the most active extracts (CSE3 and CSE4) had no acute toxicity.

Conclusions

The study highlighted the analgesic and anti-inflammatory of C. siamea stem bark. Four major families of compounds present in the plant may explain these activities: triterpenes (lupeol, oleanolic acid, ursolic acid, friedelin, betulin), flavonoids (apigenin, kaempferol, luteolin), anthraquinones (emodin), phytosterols (stigmasterol, beta-sitosterol).     

Anti-inflammatory and anti-nociceptive activities of the stem bark extracts from Allanblackia monticola STANER L.C. (Guttiferae)

THE AIM OF THIS STUDY: was to assess the anti-inflammatory and mechanism of action of Allanblackia monticola (Guttiferae). The anti-inflammatory activity "in vivo" of the methylene chloride/methanol extract, methanol and methylene chloride fractions of stem barks of Allanblackia monticola, administered orally at doses of 37.5; 75; 150 and 300 mg/kg, was evaluated on carrageenan-induced oedema in rats to determine the most active fraction. Indomethacin, inhibitor of cyclo-oxygenase was used as reference drug. The effects of the most active fraction were then examined on the rat paw oedema caused by histamine, serotonin, arachidonic acid and dextran followed by its ulcerogenic effect. The results showed that the methylene chloride fraction of Allanblackia monticola was more effective on the oedema caused by the carrageenan. The anti-nociceptive activity of the methylene chloride fraction was assessed using the acetic acid-induced abdominal constriction model, formalin test and hot plate test. At 150 mg/kg, Allanblackia monticola caused maximum inhibitions of inflammation induced by carrageenan (83.33%), by histamine (42.10%), by dextran (40.29%) and by arachidonic acid (64.28%). Allanblackia monticola (75-300 mg/kg) did not cause significant modification of the oedema induced by serotonin. Concerning the anti-nociceptive properties of the plant, the methylene chloride fraction (75-300 mg/kg) caused a dose-dependent inhibition on abdominal contractions induced by acetic acid (32.34-77.37%) and significantly inhibited the inflammatory pain caused by formalin (40.71-64.78%). Allanblackia monticola did not increase the latency time in the hot plate test. Like indomethacin (10mg/kg), the fraction at the dose of 150 mg/kg caused ulceration of the gastric mucous membrane in treated rats. These results show that Allanblackia monticola has an anti-inflammatory and analgesic activities with gastric ulcerative side effects.     

Enzyme inhibition,antioxidant and immunomodulatory activities,and brine shrimp toxicity of extracts from the root bark,stem bark and leaves of Terminalia macroptera

Ethnopharmacological relevance

The root bark, stem bark and leaves of Terminalia macroptera have been traditionally used against a variety of ailments such as wounds, hepatitis, malaria, fever, cough, and diarrhea as well as tuberculosis and skin diseases in African folk medicine. Boiling water extracts of Terminalia macroptera, administered orally, are the most common preparations of this plant used by the traditional healers in Mali. This study aimed to investigate the inhibition of the activities of α-glucosidase, 15-lipoxygenase and xanthine oxidase, DPPH scavenging activity, complement fixation activity and brine shrimp toxicity of different extracts obtained by boiling water extraction (BWE) and by ASE (accelerated solvent extraction) with ethanol, ethanol–water and water as extractants from different plant parts of Terminalia macroptera.

Materials and methods

27 different crude extracts were obtained by BWE and ASE from root bark, stem bark and leaves of Terminalia macroptera. The total phenolic and carbohydrate contents, enzyme inhibition activities (α-glucosidase, 15-lipoxygenase and xanthine oxidase), DPPH scavenging activity, complement fixation activity and brine shrimp toxicity of these extracts were evaluated. Principal component analysis (PCA) was applied for total biological activities evaluation.

Results

Several of the extracts from root bark, stem bark and leaves of Terminalia macroptera obtained by BWE and ASE showed potent enzyme inhibition activities, radical-scavenging properties and complement fixation activities. None of the extracts are toxic against brine shrimp larvae in the test concentration. Based on the results from PCA, the ASE ethanol extracts of root bark and stem bark and the low molecular weight fraction of the 50% ethanol–water extract of leaves showed the highest total biological activities. The boiling water extracts were less active, but the bark extracts showed activity as α-glucosidase inhibitors and radical scavengers, the leaf extract being less active.

Conclusion

The observed enzyme inhibition activities, radical scavenging properties and complement fixation activities may explain some of the traditional uses of this medicinal tree, such as in wound healing and against diabetes.     

Chemical constituents from the stem bark of Symplocos paniculata Thunb. with antimicrobial, analgesic and anti-inflammatory activities

Ethnopharmacological relevance

The stem bark of Symplocos paniculata Thunb. has been used to check abortion in folk medicine in India.

Aim of the study

The present study was undertaken to isolate the phytochemicals from the plant together with the evaluation of antimicrobial, analgesic and anti-inflammatory activities of the plant extract and isolated compounds.

Materials and methods

The plant extract was subjected to column chromatography for isolation of phytochemicals. The agar diffusion method was adopted for antimicrobial activity to determine MICs. Ethanolic extract and isolated compounds were selected for investigating their analgesic activity on acetic acid-induced writhing response in mice. The anti-inflammatory activity was performed on carrageenan-induced paw edema in rats.

Results

The stem bark of the plant afforded seven compounds, 4-(8-hydroxyethyl) cyclohexan-1-oic acid (1); androst-5(6)-ene 17-one 3β-O-(β-d-glucopyranoside) (2); 9β,25-cyclo 3β-O-(β-d glucopyranosyl)-echynocystic acid (3); 9β,19-cyclo 24-methylcholan-5,22-diene 3β-O-{β-d-glucopyranosyl (1 → 6) α-l-rhamnopyranoside} (4); 30-ethyl 2α,16α-dihydroxy 3β-O-(β-d-glucopyranosyl) hopan-24-oic acid (5); 32,33,34-trimethyl-bacteriohopan-16-ene 3-O-β-d-glucopyranoside (6) and flavone 3′,4′,5′,6-tetramethoxy 7-O-β-d-glucopyranosyl (1 → 3) β-d-glucopyranoside (7). The extract and isolated compounds exhibited antimicrobial, analgesic and anti-inflammatory activities.

Conclusion

The present study concludes that ethanolic extract of the plant and its constituents having significant antimicrobial, analgesic and anti-inflammatory activities.     

Anti-ulcer, anti-inflammatory and antioxidant activities of the n-butanol fraction from Pteleopsis suberosa stem bark

Pteleopsis suberosa Engl. et Diels (Combretaceae) is a tree distributed in many African countries. The decoction from the stem bark is orally administered for the treatment of gastric ulcers in traditional medicine. Previous pharmacological studies reported the anti-ulcer activity of extracts from P. suberosa stem bark. In the present study, the anti-ulcer and anti-inflammatory effects of the n-butanol fraction (RBuOH) obtained from a methanol extract of P. suberosa bark were investigated on ethanol-induced gastric ulcers in rats and carrageenan-induced paw oedema in mice. Misoprostol (0.50 mg/kg, p.o.) and indomethacin (8.00 mg/kg, p.o.) were used as positive controls for anti-ulcer and anti-inflammatory activities, respectively. Results showed that RBuOH treatment significantly reduced the incidence of gastric lesions (50 mg/kg, P<0.05; 100 and 200 mg/kg, P<0.01) and restored the decreased levels of total sulfhydryl groups (T-SH) and non-protein sulfhydryl groups (NP-SH) (50, 100 mg/kg, P<0.05; 200 mg/kg, P<0.01) in the stomach homogenate. Moreover, RBuOH treatment attenuated MDA levels as index of lipid peroxidation in gastric mucosa. Administration of RBuOH at the same dosage (50, 100 and 200 mg/kg) reduced significantly (P<0.01) carrageenan-induced paw oedema in dose-dependent manner (from 42.81% to 87.81% inhibition, 5h after carrageenan injection). The anti-inflammatory effect of RBuOH at 200 mg/kg was comparable with that of indomethacin. Finally, RBuOH proved to possess elevated free radical scavenger capacity on 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay (IC(50) 23.48 microg/ml) which may contribute to the observed anti-ulcer and anti-inflammatory activities.     

老鸭嘴化学成分研究

目的:对老鸭嘴乙醇提取物的活性部位进行化学成分研究.方法:对老鸭嘴提取液不同极性部位进行醛糖还原酶抑制活性筛选,活性部位应用常规柱色谱及制备高效液相手段相结合进行化学成分分离,采用波谱技术对所得到的化合物进行结构鉴定.结果:从乙酸乙酯部位中分离鉴定了8个化合物,分别为新化合物8-羟基-8-甲基-9-亚甲基-环戊烷[7,11]-1,4,6-三羟基-四氢化萘-12-酮,命名为山牵牛素A(1),3,4-二氢4,5,8-三羟基-2-(3-甲基-2-丁烯基)萘[2,3-b]环氧乙烯-1(2H)-酮(2),8-(β-葡萄糖吡喃型-O-)-3,4-二氢-2-(3-甲基-2-丁烯基)萘[2,3-b]环氧乙烯-1(2H)-酮(3),高良姜素(4),槲皮素(5),木犀草素(6),5,6,3’,4’-四羟基-3,7-二甲氧基黄酮(7)和羽扇豆醇(8).结论:老鸭嘴乙酸乙酯提取物有明显的抑制醛糖还原酶活性,从该提取物中分离得到1个新的四氢化萘衍生物山牵牛素A,首次从该属植物中分离得到环氧萘类化合物及其苷,还有4个黄酮类化合物,1个三萜化合物.     

长穗桑茎皮中的酚类成分及其抗炎和细胞毒活性

目的:研究长穗桑茎皮中具有抗炎和细胞毒活性的化学成分。方法:采用各种柱色谱对长穗桑茎皮95%乙醇提取物的醋酸乙酯部位进行分离纯化,通过NMR,MS等波谱分析手段鉴定化合物结构。结果:从醋酸乙酯部位中分离得到9个酚类化合物,其中6个黄酮类化合物,3个二苯乙烯类化合物。分别鉴定为槲皮素(1),5,7,3,′4′-四羟基-3-甲氧基黄酮(2),norartocarpanone(3),二氢山柰酚(4),euchrenone a7(5),morachalcone A(6),白藜芦醇(7),高白藜芦醇(8),4′-异戊烯基高白藜芦醇(9)。化合物1~8分别进行了抗炎和细胞毒活性筛选。结论:化合物1~9均为首次从该植物中分离得到。其中化合物6和8浓度在1.0×10-5mol.L-1时对血小板活化因子刺激的多形核白细胞β-葡萄糖苷酸酶释放的抑制率分别为76.8%,94.2%;化合物2和8分别对人卵巢癌细胞(A2780)和人胃癌细胞(BGC-823)有选择性细胞毒活性,IC50分别为0.66,1.31μmol.L-1。     

Antioxidant and anti-inflammatory activities of the phenolic extracts of Sapium sebiferum (L.) Roxb. leaves

Ethnopharmacological relevance

The leaves of Sapium sebiferum have long been used in Traditional Chinese Medicine (TCM) for the treatment of eczema, shingles, edema, swelling, ascites, scabs, and snakebites, among other maladies.

Aim of this study

The present study aimed to investigate the antioxidant and anti-inflammatory effects of the phenolic extracts of Sapium sebiferum leaves using in vitro and in vivo models.

Materials and methods

The in vitro antioxidant activities of the extracts were measured using common chemical methods (total phenolic content; total flavonoid content; scavenging of DPPH·, ABTS+·, superoxide, and nitrite radicals; reducing power; β-carotene bleaching; and FTC assays). The in vivo topical anti-inflammatory activities were tested using the 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced dermatitis animal model. The SOD and CAT activities and the GSH content of ear tissue were also determined using test kits.

Results

The extracts of Sapium sebiferum leaves exhibited strong in vitro antioxidant activities. They also showed significant (P<0.001) and dose-dependent anti-inflammatory activities in an acute dermatitis model at the doses of 0.03 mg/ear, 0.1 mg/ear, and 0.3 mg/ear. The application of Sapium sebiferum leaf extracts increased the SOD and CAT activities and the GSH content relative to those of the TPA treatment group. The anti-inflammatory effect of the Sapium sebiferum leaf extract was positively correlated with its antioxidant activity.

Conclusion

These results demonstrate that Sapium sebiferum leaf extract is an effective anti-inflammatory agent in the TPA-induced dermatitis model, and its anti-inflammatory effect is related, at least in part, to its antioxidant activity.     

Evaluation of the anti-inflammatory and anti-proliferation tumoral cells activities of Antrodia camphorata, Cordyceps sinensis, and Cinnamomum osmophloeum bark extracts

The extracts of chloroform (1) and methanol (2) from Antrodia camphorata (AC), and chloroform (3) and n-butanol (4) fractions of methanol extract from Cordyceps sinensis (CS), and hexane (5), ethyl acetate (6), and methanol (7) from Cinnamomum osmophloeum bark (CO) were evaluated for their anti-inflammatory as well as tumor-cell growth inhibitory activities in vitro. All the tested extracts dose dependently inhibited the enhanced production of inflammatory mediators such as nitric oxide (NO) through reducing inducible NO synthase expression, and cytokines (tumor necrosis factor (TNF)-alpha and interleukin (IL)-12 in LPS/IFN-gamma activated murine peritoneal macrophages. In addition, extracts 1 from AC, and 5 and 6 from CO significantly arrest the mitogen-stimulated spleen cells in G0/G1 stage. On the other hand, all these extracts were also evaluated for their tumor-cell proliferation activities in different type of cancer cell lines such as Jurkat, HepG2, PC 3, Colon 205, and MCF 7 as well as normal PBMCs. Compared to untreated controls, the extracts 1, 2, and 4-7 were most active and inhibited Jurkat cells with IC50 value of 22, 40, 18, 4, 5, and 45 microg/ml, respectively. In addition, the extracts 5, 6, and 7 from CO showed potent growth inhibition of HepG2 and PC 3 with IC50 values of 35, 80, 55 microg/ml; and 42, 125, and 50 microg/ml, respectively. Similarly, the extracts 1 and 5 inhibited the growth of Colon 205 and MCF 7 cells with IC50 values of 65, 33; and 95 and 30 microg/ml, respectively. Interestingly, none of the tested extract has shown cytotoxicity towards normal PBMCs up to the concentration range studies (0-150 microg/ml). Taken together, these data suggest that the anti-inflammatory and anti-cancer properties of AC, CS, and CO might result from the growth inhibition of NO, TNF-alpha and IL-12, and tumor cells proliferation, respectively.     

Effects of Catalpa ovata stem bark on atopic dermatitis-like skin lesions in NC/Nga mice

Ethnopharmacological relevance

The stem bark of Catalpa ovata has been used as a traditional herbal medicine for the treatment of various inflammatory diseases such as itching and scabies.

Aim of the study

In the present study, we investigated the anti-AD effects of Catalpa ovata stem bark on Dermatophagoides farinae-induced AD in a NC/Nga mouse AD model. We determined dermatitis score, histology, IgE, cytokines, and chemokines related to hypersensitive immune responses in AD. The mechanism of action was also investigated using HaCaT cells.

Materials and methods

We investigated the topical effects of Catalpa ovata stem bark on AD-like skin lesions in NC/Nga mice. Five category-experiments were performed, including assessment of dermatitis score; histological analysis of dorsal skin lesions; quantitative measurement of serum total IgE; quantitative measurement of cytokines (IL-1β, IL-4, IL-5, IL-6, IL-13, TNF-α) from dorsal tissue; and RT-PCR analysis of for TSLP and TARC mRNA expression in HaCaT cells.

Results

The clinical dermatitis score was significantly lower in Catalpa ovata extract (COE) groups than in the control group. Histological analysis showed that COE inhibited hypertrophy and hyperkeratosis of the epidermis, intracellular edema, and reduced the infiltration of inflammatory cells. COE significantly inhibited serum total IgE; Th2 cytokines IL-4, IL-5 and IL-13; pro-inflammatory cytokines IL-1β, IL6 and TNF-α; the Th2 chemokine TARC and the pro-Th2 cytokine TSLP.

Conclusion

These results demonstrate that Catalpa ovata stem bark may be a useful external medicine for treatment of AD. Further investigation is necessary to determine appropriate COE dosage and to evaluate the safety of this medicinal herb.     

Intestinal anti-inflammatory activity of hydroalcoholic extracts of Phlomis purpurea L. and Phlomis lychnitis L. in the trinitrobenzenesulphonic acid model of rat colitis.

Ethnopharmacological relevance

Different species from genus Phlomis, frequently native from the the eastern Mediterranean zone, have been used in traditional medicine as an anti-inflammatory remedy. Among other constituents, they contain polyphenols that show antioxidant properties, which are interesting for the treatment of inflammatory pathologies associated with oxidative stress in humans, such as inflammatory bowel disease (IBD). The aim of this study was to evaluate the intestinal anti-inflammatoy effect of hydroalcoholic extracts of Phlomis lychnitis and P. purpurea in the trinitrobenzenesulphonic acid (TNBS) model of rat colitis, a well characterized experimental model with some resemblance to human IBD.

Materials and methods

Hydroalcoholic extracts of both plants were characterized by determining their polyphenolic content and then assayed in the TNBS model of rat colitis. For this purpose, female Wistar rats were assigned to seven groups (n=10): healthy control, untreated TNBS-colitis and five TNBS- colitis groups treated with Phlomis lychnitis (10 and 20 mg/kg), P. purpurea (10 and 25 mg/kg) and sulphasalazine (200 mg/kg), as a positive control. Treatments started the same day of TNBS colitis induction, and rats were sacrificed one week later. Colonic inflammation was evaluated both histologically and biochemically.

Results

The histological (macroscopic and microscopic) analysis of colonic samples revealed that both extracts showed an anti-inflammatory effect, which was confirmed biochemically by a decreased colonic MPO activity, a maker of neutrophil infiltration, an increased colonic glutathione content, which counteracts the oxidative status associated with the inflammatory process, and a down-regulated iNOS expression. However, only the extract of P. purpurea reduced the expression of the proinflammatory cytokines IL-1β and IL-17, the chemokines CINC-1 and MCP-1, as well as the adhesion molecule ICAM-1, ameliorating the altered immune response associated with the colonic inflammation. Furthermore, both P. lychnitis and P. purpurea extracts were able to significantly increase the expression of markers of epithelial integrity such as MUC-2, MUC-3 and villin, thus revealing an improvement in the altered colonic permeability that characterizes colonic inflammation.

Conclusions

Both extracts showed intestinal anti-inflammatory activity in the TNBS model of rat colitis, thus confirming their traditional use in digestive inflammatory complaints. In addition to their antioxidant properties, other mechanisms can contribute to this beneficial effect, like an improvement in the intestine epithelial barrier and a downregulation of the immune response.     

Antiplasmodial activity of extracts from seven medicinal plants used in malaria treatment in Cameroon

Aim of the study

In a search for new plant-derived biologically active compounds against malaria parasites, we have carried out an ethnopharmacological study to evaluate the susceptibility of cultured Plasmodium falciparum to extracts and fractions from seven Cameroonian medicinal plants used in malaria treatment. We have also explored the inhibition of the Plasmodium falciparum cysteine protease Falcipain-2.

Materials and methods

Plant materials were extracted by maceration in organic solvents, and subsequently partitioned or fractionated to afford test fractions. The susceptibility of erythrocytes and the W2 strain of Plasmodium falciparum to plant extracts was evaluated in culture. In addition, the ability of annonaceous extracts to inhibit recombinant cysteine protease Falcipain-2 was also assessed.

Results and discussion

The extracts showed no toxicity against erythrocytes. The majority of plant extracts were highly active against Plasmodium falciparumin vitro, with IC₅₀ values lower than 5 μg/ml. Annonaceous extracts (acetogenin-rich fractions and interface precipitates) exhibited the highest potency. Some of these extracts exhibited modest inhibition of Falcipain-2.

Conclusion

These results support continued investigation of components of traditional medicines as potential new antimalarial agents.     

Potential genotoxicity of plant extracts used in Ethiopian traditional medicine

Aim of the study

Although traditional herbal medicines are widely used in Ethiopia, no information is available on their potential genotoxicity. In the present study, hydroalcoholic extracts of Glinus lotoides, Plumbago zeylanica, Rumex steudelii and Thymus schimperi were evaluated for their DNA damaging effects using the comet assay.

Material and methods

Mouse lymphoma L5178Y cells were exposed to different concentrations of the extracts for 3 h with and without metabolic activation (S9-mix) using 4-nitroquinoline-N-oxide and benzo(a)pyrene as positive controls, and vehicles as negative controls.

Results

In the absence of S9, all extracts were found to induce significant DNA damage without affecting the cell viability. T. schimperi and R. steudelii were the most potent DNA-damaging extracts, and G. lotoides and P. zeylanica the least potent. The addition of S9 had different effects on the DNA damage induced by the extracts: it lowered the DNA damaging effect of P. zeylanica, did not affect the DNA damaging effect of T. schimperi, and increased the DNA damaging effects of R. steudelii and G. lotoides.

Conclusion

The findings of the present study suggest that all extracts evaluated have a genotoxic potential in vitro which needs to be substantiated by further studies.     

Screening for polyphenols,antioxidant and antimicrobial activitiesof extracts from eleven Helianthemum taxa (Cistaceae) used in folk medicine in south-eastern Spain

Ethnopharmacological relevance

The Helianthemum genus contains approximately one hundred taxa. Some of them are important medicinal plants used in several countries for many different purposes. However, studies addressing the phytochemistry of many of these species or their biological activities are currently nonexistent.

Aim of the study

To perform a comparative analysis of the qualitative composition of secondary metabolites and biological activities of the leaves of the most commonly distributed and used Spanish Helianthemum taxa in order to find a relationship between chemotype, biological activity and uses.

Materials and methods

water and 80% methanolic extracts derived from 11 different Helianthemum taxa were analyzed for their phytochemical composition using standard methods. Furthermore, HPLC analysis was performed for the estimation of gallic acid, ellagic acid, tannins and flavonols as marker compounds. The antioxidant activity was measured by employing the scavenging activity on DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonate) radicals. The 80% methanolic extracts were evaluated for antibacterial (Gram-positive Staphylococcus aureus, Enterococcus faecalis and Listeria monocytogenes and Gram-negative Escherichia coli and Salmonella enterica) activity using the micro dilution technique.

Results

The total polyphenolic content and antioxidant capabilities differed significantly among the Helianthemum leaf extracts. A strong correlation between total phenolic content, antioxidant properties and antimicrobial activity was found. The polyphenolic profile was specific for each taxon. Whereas Helianthemum alypoides, Helianthemum cinereum subsp. rotundifolium, Helianthemum hirtum, Helianthemum asperum, and Helianthemum marifolium subsp. marifolium were characterized by the presence of gallic acid, egallic derivatives and ellagitannins; the polyphenolic profile of Helianthemum apenninum subsp. cavanillesianum, Helianthemum syriacum and Helianthemum polygonoides was mostly based on flavonoids. Helianthemum cinereum, Helianthemum alypoides and Helianthemum marifolium consistently presented the strongest radical scavenging activity (in water extracts EC₅₀ ranges from 29.88 to 38.1 against DPPH and from 8.11 to 20.8 against ABTS, and in 80% MeOH extracts from 25.3 to 31.8 against DPPH and from 6.15 to 8.6 against ABTS), total phenol content (>117 mg GAE/l) and antimicrobial activities.

Conclusion

The Helianthemum taxa used in folk medicine did not cluster in a unique section, being equally distributed in two out of the four sections analysed. There was not a clear relationship between the chemotype, based on the polyphenolic composition of the taxa, and their taxonomical classification. However, the composition of the methanolic and water extracts from the leaves of plants belonging to the Helianthemum genus was strongly related to their medicinal uses.     

Anti-inflammatory activity of extracts and 11,13-dihydrozaluzanin C from Gochnatia polymorpha ssp. floccosa trunk bark in mice

Aim of this study

Gochnatia polymorpha ssp. floccosa (Asteraceae), popularly known as “cambará”, is well recognized in Brazilian traditional medicine to treat the respiratory tract inflammatory diseases and rheumatism. However, no scientific data have been published to support this ethnopharmacological use. This work aimed to evaluate the anti-inflammatory action of its ethanol (EEGP) extract, ethyl acetate (EA), dichloromethane (DCM), petroleum ether (PE) butanolic (BT) fractions, and the isolated compounds bauerenyl acetate (GPC1) and 11,13-dihydrozaluzanin C (GPC2).

Materials and methods

The anti-inflammatory activities were evaluated in mice subjected to paw oedema and carrageenan-induced air pouch inflammation models.

Results

The oral administration of EEGP (30, 100 and 300 mg/kg), DCM (50 mg/kg), BT (20 mg/kg) and GPC2 (10 and 30 mg/kg), but not EP and EA fractions (both at 30 mg/kg) and GPC1 (1 and 10 mg/kg), significantly inhibited the paw oedema induced by carrageenan (41 ± 13, 39 ± 5 and 60 ± 10% for EEGP at the three doses, respectively; 44,47 ± 12.8 and 70.19 ± 11.52% for DCM and BT, respectively; and 29.52 ± 4.8 and 31.67 ± 5.4%, for 11,13-dihydrozaluzanin C at 10 and 30 mg/kg, respectively) compared to control group. The oral administration of EEGP (30, 100 and 300 mg/kg) inhibited the carrageenan-induced leukocyte migration in the air pouch model (37.2 ± 12.5, 62.6 ± 5.0 and 54.3 ± 6.8%, respectively), as well as protein extravasation (47.9 ± 12.5, 51.7 ± 15.2 and 60.9 ± 13.7%, respectively) compared to control group. In a similar way, DCM (50 mg/kg) or GPC2 (10 mg/kg), but not BT (20 mg/kg) given by oral route inhibited leukocyte infiltration into the pouch (29.5 ± 10.6 and 54.4 ± 21.8%, respectively). Also DCM and GPC2 significantly reduced the protein levels in the supernatants (52.4 ± 15.0 and 51.83 ± 16.9%, respectively).

Conclusion

The results suggest that EEGP, and BT and DCM fractions from G. polymorpha possess anti-inflammatory activity and probably the compound 11,13-dihydrozaluzanin C was responsible, at least in part, for this action.     

Antitubercular activity of Arctium lappa and Tussilago farfara extracts and constituents

Ethnopharmacological relevance

Arctium lappa and Tussilago farfara (Asteraceae) are two plant species used traditionally as antitubercular remedies. The aim of this study was (i) to screen Arctium lappa and Tussilago farfara extracts for activity against Mycobacterium tuberculosis and (ii) to isolate and identify the compound(s) responsible for this reputed anti-TB effect.

Materials and methods

The activity of extracts and isolated compounds was determined against Mycobacterium tuberculosis H₃₇R_v using a high throughput spot culture growth inhibition (HT-SPOTi) assay.

Results

The n-hexane extracts of both plants, the ethyl acetate extract of Tussilago farfara and the dichloromethane phase derived from the methanol extract of Arctium lappa displayed antitubercular activity (MIC 62.5 μg/mL). Further chemical investigation of Arctium lappa led to the isolation of n-nonacosane (1), taraxasterol acetate (2), taraxasterol (3), a (1:1) mixture of β sitosterol/stigmasterol (4), isololiolide (5), melitensin (6), trans-caffeic acid (7), kaempferol (8), quercetin (9), kaempferol-3-O-glucoside (10). Compounds isolated from Tussilago farfara were identified as a (1:1) mixture of β sitosterol/stigmasterol (4), trans-caffeic acid (7), kaempferol (8), quercetin (9), kaempferol-3-O-glucoside (10), loliolide (11), a (4:1) mixture of p-coumaric acid/4-hydroxybenzoic acid (12), p-coumaric acid (13). All compounds were identified following analyses of their physicochemical and spectroscopic data (MS, ¹H and ¹³C-NMR) and by comparison with published data. This is the first report of the isolation of n-nonacosane (1), isololiolide (5), melitensin (6) and kaempferol-3-O-glucoside (10) from Arctium lappa, and of loliolide (11) from Tussilago farfara. Amongst the isolated compounds, the best activity was observed for p-coumaric acid (13) (MIC 31.3 μg/mL or 190.9 μM) alone and in mixture with 4-hydroxybenzoic acid (12) (MIC 62.5 μg/mL).

Conclusions

The above results provide for the first time some scientific evidence to support, to some extent, the ethno-medicinal use of Arctium lappa and Tussilago farfara as traditional antitubercular remedies.     

Antihypertensive effects of isoquercitrin and extracts from Tropaeolum majus L.: evidence for the inhibition of angiotensin converting enzyme

Aim of the study

Previous studies have shown that the extracts obtained from Tropaeolum majus L. exhibit pronounced diuretic properties. In the present study, we assessed whether the hypotensive and/or antihypertensive mechanism of hydroethanolic extract (HETM), semi-purified fraction (TMLR) obtained from T. majus and the flavonoids isoquercitrin (ISQ) and kaempferol (KPF) can be mediated by their interaction with angiotensin converting enzyme (ACE).

Methods and methods

Firstly, to evaluate changes in mean arterial pressure (MAP), different groups of normotensive and spontaneously hypertensive rats (SHR) were orally and intraduodenally treated with HETM (10-300 mg/kg) and TMLR (12.5-100 mg/kg) and intravenously treated with ISQ and KPF being later anesthetized with ketamine (100 mg/kg) and xylazine (20 mg/kg). The left femoral vein and the right carotid artery were isolated, and polyethylene catheters were inserted for ISQ and KPF (0.5-4 mg/kg) administration and blood pressure recording, respectively. The plasmatic ACE activity was evaluated to indirect fluorimetry, in serum samples after orally treatment with HETM, TMLR, ISQ and KPF.

Results

The oral administration of the HETM and its TMLR significantly reduced, in a dose-dependent manner, the MAP in both normotensive and SHR. In addition, these preparations significantly decreased the MAP for up to 3 h after the administration of the extract. Additionally, the intravenous administration of ISQ, but not KPF, decreased MAP in rats. Otherwise, neither the extracts nor ISQ affected the heart rate. The oral administration of the HETM, TMLR or ISQ reduced ACE activity in serum samples at 90 min after administration. Finally, the intravenous administration of ISQ caused a significant reduction in the hypertensive response to angiotensin I, but not angiotensin II in normotensive rats.

Conclusion

Our results show that the hypotensive effects caused by the HETM, as well as by its TMLR, may be associated with the high levels of the flavonoid ISQ found in this plant. In addition, ISQ-induced hypotension in rats is an event dependent on the inhibition of angiotensin II generation by ACE.     

Antiprotozoal screening and cytotoxicity of extracts and fractions from the leaves,stem bark and root bark of Alstonia congensis

Ethnopharmacological relevance

To evaluate the antiprotozoal activity and cytotoxicity of extracts and fractions from the leaves, root bark and stem bark of Alstonia congensis (Apocynaceae), used in traditional medicine against parasitic diseases.

Materials and methods

The aqueous and 80% MeOH extracts, and a series of fractions and subfractions from the leaves, stem and root bark of Alstonia congensis were tested in vitro for their antiprotozoal activity against Trypanosoma brucei brucei, Trypanosoma cruzi, Lesihamania infantum and the chloroquine and pyrimethamine-resistant K1 strain of Plasmodium falciparum. Their cytotoxicity on MRC-5 cells (human lung fibroblasts) was evaluated as well.

Results

The aqueous and 80% MeOH extracts and a series of subfractions of each plant part exhibited pronounced antiprotozoal activity against the K1 strain of Plasmodium falciparum with IC₅₀ values ranging from 2 to 5 µg/ml, and good activity against Trypanosoma brucei brucei and Trypanosoma cruzi with IC₅₀ values ranging between 5 and 10 µg/ml. The residual 80% MeOH extract from the leaves, and the total alkaloid extract from stem and root bark were the only subfractions active against Leishmania infantum with IC₅₀ values <10 µg/ml. None of the samples from the root bark was cytotoxic against MRC-cell lines (CC₅₀>64 µg/ml). In general, the aqueous extract (traditional decoction) showed the highest selectivity, especially against Plasmodium falciparum.

Conclusion

These results can partly support and justify the traditional use of these plant parts of Alstonina congensis as raw materials for the preparation of traditional remedies to treat parasitic diseases such as malaria and trypanosomiasis.