Isolation of major phenolics from Launaea spinosa and their protective effect on HepG2 cells damaged with t-BHP

Context: Some Launaea species (Asteraceae) are used traditionally to treat liver oxidative stress.

Objective: The present study investigates the protective effects of isolated compounds from Launaea spinosa Sch. Bip. (Asteraceae) against oxidative stress on t-BHP-induced HepG2 cells.

Materials and methods: Major phenolic content from flowering aerial parts of L. spinosa was isolated and identified. The protective effects of isolated compounds (10 and 20?μM) against oxidative stress induced by tert-butyl hydroperoxide (t-BHP) in HepG2 cells were investigated through the measurement of aspartate aminotransferase (AST), alanine transaminase (ALT), and superoxide dismutase (SOD) levels.

Results: A new phenolic compound identified as 2,3-diferulyl R,R-(+) methyl tartrate (6), in addition to five known metabolites, esculetin (1), esculetin-7-O-d-glucoside (cichoriin) (2), fertaric acid (3), acacetin-7-O-d-glucoside (4), and acacetin-7-O-d-glucuronic acid (5), were isolated. Oxidant-induced damage by 200?μM t-BHP in HepG2 cells was inhibited by compounds 1, 4, and 5 (10 and 20?μM), or quercetin (10?μM; positive control). The protective effects of compounds 1, 4, and 5 were associated with decreasing in AST, ALT, and SOD levels. Compound 4 (20?μM) decreased the AST level from 128.5?±?13.9 to 7.9 ±1.8?U/mL. Meanwhile, compound 1 (20?μM) decreased ALT activity from 20.3?±?7.0 to 7.6?±?2.4?U/mL, while compound 5 decreased SOD levels from 41.6?±?9.0 to 28.3?±?3.4?mU/mg.

Conclusion: The major phenolic compounds isolated from L. spinosa displayed a significant cytoprotective effect against oxidative stress, leading to maintenance of the normal redox status of the cell.     

Evaluation of the cytotoxic potential of a new pentacyclic triterpene from Rhododendron arboreum stem bark

Context: Traditionally, Rhododendron arboreum Sm. (Ericaceae) is a very important medicinal plant having oxytocic, estrogenic, anti-inflammatory, analgesic and hepatoprotective activities; it also inhibits the prostaglandin synthetase.

Objectives: This study determines the cytotoxic potential of 15-oxoursolic acid isolated from R. arboreum against selected human cancer cell lines.

Materials and methods: Extraction from stem bark (5?kg) of R. arboreum was performed with methanol, which was successively partitioned into hexane, dichloromethane and ethyl acetate fractions, respectively. The new antitumor agent [15-oxoursolic acid (1)] was isolated from ethyl acetate fraction through column chromatography. Structure elucidation of new compound was performed through extensive spectroscopy i.e., IR, MS and 1D and 2D NMR. Cytotoxicity of isolated compound was determined at doses 5–100?μM for a period of 72?h on specified human cancer cell lines [renal cell carcinoma (A498), non-small cell lung (NCI-H226), squamous cell carcinoma (H157) and human ovarian carcinoma (MDR-2780AD)].

Results: Structure of isolated compound was characterized as 15-oxoursolic acid on the basis of various extensive spectroscopic techniques. 15-Oxoursolic acid revealed considerable anticancer activity with IC₅₀ values of 2.3?±?0.1?μM, 4.9?±?0.2?μM, 9.2?±?0.2?μM and 10.3?±?0.1?μM against MDR 2780AD, Hep G2, H157 and NCI-H226, respectively, while in the case of A498, the activity was good (IC₅₀ 32.8?±?1.2?μM).

Conclusions: This study highlighted the potential of 15-oxoursolic acid to be further explored as a new lead compound for cancer chemotherapy.     

Amelioration of hyperglycaemia and modulation of antioxidant status by Alcea rosea seeds in alloxan-induced diabetic rats

Context: Alcea rosea L. (Malvaceae) has various medicinal uses including anticancer, anti-inflammatory and analgesic properties. However, there is no report on its antidiabetic activity.

Objective: Alcea rosea seed extracts were evaluated for antihyperglycaemic and antioxidative potential in diabetic rats.

Materials and methods: Single intra-peritoneal injection of alloxan (130?mg/kg b.w.) was used for induction of diabetes in Albino Wistar rats. Antihyperglycaemic and antioxidant activities of methanol and aqueous extracts of Alcea rosea seed (100 and 300?mg/kg b.w.), administered orally on daily basis for 15 days, were assessed in vivo for fasting blood glucose level and antioxidant status of liver and pancreas. Metformin was used as a positive control.

Results: Aqueous and methanol extracts (300?mg/kg b.w.) decreased blood glucose level in diabetic rats by 24% and 46%, respectively. Administration of aqueous and methanol extracts at 300?mg/kg b.w. significantly (p?2O₂ decomposed/min/mg of protein), respectively. Similar results were observed for pancreas.

Discussion and conclusions: Antihyperglycaemic and antioxidative potentials of Alcea rosea seeds suggest its usefulness in management of diabetes and its complications. This is the first report on antidiabetic activity of this plant.     

Comparative pharmacokinetics of chlorogenic acid in beagles after oral administrations of single compound,the extracts of Lonicera japanica,and the mixture of chlorogenic acid,baicalin, and Forsythia suspense

Context: Chlorogenic acid (ChA) is the major compound in Shuang-Huang-Lian (SHL), which is mainly composed of ChA, baicalin, and Forsythia suspense Thunb Vahl.

Objective: The effects of co-existing compounds in SHL and Lonicera japanica Thunb on the absorption of ChA was investigated.

Materials and methods: According to 3?×?3 Latin-square test, ChA alone, the extracts of Lonicera japanica, or the mixture of ChA, baicalin and Forsythia suspense (ChA effective doses is 60?mg/kg) was separately given to six beagles for seven days. The oral pharmacokinetic parameters of ChA in plasma, urine and faeces were quantified by HPLC/UV and analyzed.

Results: The pharmacokinetic parameters of ChA alone, the extracts of Lonicera japanica, and the mixture of ChA, baicalin, and Forsythia suspense were as followed: C_max (2.350?±?0.483, 1.655?±?0.576, 2.332?±?0.606?μg/mL), AUC_0-∞ (6.324?±?1.853, 4.216?±?1.886, 6.074?±?1.473?μg·h/mL), t_1/2 (0.911?±?0.187, 1.204?±?0.309, 1.094?±?0.193?h), and T_max (1.861?±?0.499, 1.000?±?0.459, 1.833?±?0.279?h). Accumulative fraction excretion of ChA in urine were 0.73?±?0.55, 1.25?±?1.23, 1.05?±?0.96%, while that in faeces were 0.68?±?0.94, 0.19?±?0.40, and 1.76?±?3.57%.

Discussion and conclusion: Co-existing compounds in SHL have no effect on the absorption of ChA, while the concomitant compounds in Lonicera japanica could decrease that of ChA. ChA in Beagles might have high biological transformation.     

The anti-inflammatory activity of several flavonoids isolated from Murraya paniculata on murine macrophage cell line and gastric epithelial cell (GES-1)

Context Murraya paniculata (L.) Jack (Rutaceae), Qianlixiang in Chinese, is distributed in China. As an important traditional Chinese medicine (TCM), it demonstrates many bioactivities, such as febrifuge, astringent, anti-dysenteric, and tonic.

Objective: The objective of this study is to evaluate the anti-inflammatory effect of three flavonoids isolated from M. paniculata in lipopolysaccharide (LPS)-activated murine macrophage cell line and ethanol-induced gastric damage on gastric epithelial cell (GES-1).

Materials and methods Three identified flavonoids were isolated from stems and leaves of M. paniculata using ultra performance liquid chromatography (UPLC). Cell viability was measured with MTT, mouse peritoneal macrophages and GES-1 cells were incubated with 0, 0.01, 0.1, 1, 10, and 100?μM P1, P3 and P8 for 24, 48, and 72?h. The inhibitory effect of pretreatment with various concentrations of 5,7,3′,4′,5′-pentamethoxyflavone (P1), 5,7,3′,4′-tetramethoxyflavone (P3), or 5-desmethylnobiletin 5-hydroxy-6,7,8,3′,4′-pentameth-oxyflavone (P8) ranging from 0.03 to 30?μM on nitric oxide (NO) secretion was quantified by the Griess assay for 24 and 48?h, while interleukin-6 (IL-6) was measured by ELISA for 24 and 48?h.

Results The effects of P1, P3, and P8 on mouse peritoneal macrophages and GES-1 cells were not attributable to cytotoxic effects at the doses of 0–10?μM. The IC₅₀ value of P1 is 53.40?μM, P3 is 120.98?μM, and P8 is 10.73?μM. The concentration of the three flavonoids had the best effects of anti-inflammation upon NO inhibition at the dose of 3?μM. P3 had the highest inhibition on IL-6 production. The GES-1 cells pretreated with three flavonoids showed a significant increase in the level of NO (P1: 7.94?±?0.0635?μM, P3: 8.81?±?0.0159?μM, and P8: 8.51?±?0.0522?μM) at 24?h and a more significant increase at 48?h (P1: 9.34?±?0.0975?μM, P3: 11.9?±?0.0672?μM, and P8: 9.34?±?0.0454?μM).

Discussion and conclusion The current results suggested that the anti-inflammatory activity of three flavonoids was mainly manifested in the reduction of production of NO and IL-6 production. Analysis of the structure–activity relationship indicated that the double bond at C₂–C₃ and the position of the B ring at C₂/C₃ seemed to be indispensable for the anti-inflammatory activity.     

Antioxidant capacity of Typha angustifolia extracts and two active flavonoids

Context: The pollen of Typha angustifolia L. (Typhaceae) has been used as a traditional Chinese medicine for improving the microcirculation and promoting wound healing. Flavonoids are the main constituent in the plant, but little is known about the antioxidant activity of the principal constituent of the pollen in detail.

Objectives: To assess the antioxidant activities of ethanol and water extracts and two constituents of the pollen.

Materials and methods: Plant material (1?g) was extracted by 95% ethanol and water (10?mL?×?2, 1?h each), respectively. The extracted activities (0.8–2.6?mg/mL) were measured by DPPH and the reducing activity of ferric chloride (1.7–2.6?mg/mL). Typhaneoside and isorhamnetin-3-O-neohesperidoside (I3ON) (2.8–70?μmol/L) were investigated on the relationship between NO, MDA and SOD in HUVECs treated with 100?μg/mL of LPS for 24?h.

Results: Nine compounds were identified by UPLC-MS. Ethanol extract showed IC₅₀ values in DPPH (39.51?±?0.72) and Fe³⁺ reducing activity (82.76?±?13.38), higher than the water extract (50.85?±?0.74) and (106.33?±?6.35), respectively. Typhaneoside and I3ON promoted cell proliferation at the respective concentration range of 2.8 to 70?μmol/L (p?p?p?p?Conclusions: The constituents from Typha angustifolia could be a novel therapeutic strategy for LPS-induced inflammation.     

Caffeic acid methyl and ethyl esters exert potential antidiabetic effects on glucose and lipid metabolism in cultured murine insulin-sensitive cells through mechanisms implicating activation of AMPK

Context: Caffeic acid methyl (CAME) and ethyl (CAEE) esters stimulate glucose uptake and AMP-activated protein kinase (AMPK) in C2C12 myocytes (ATCC^® CRL-1772^TM).

Objective: Effects of CAME and CAEE were now assessed on myocyte glucose transporter GLUT4 activity and expression, on hepatic gluconeogenesis and on adipogenesis as well as major underlying signaling pathways.

Materials and methods: GLUT4 protein translocation was studied in L6 GLUT4myc cells, glucose-6-phospatase (G6Pase) in H4IIE hepatocytes and adipogenesis in 3T3-L1 adipocytes. Key modulators were measured using western immunoblot. Cells were treated for 18?h with either CAME or CAEE at various concentrations (12.5–100?μM).

Results: Myocyte glucose uptake rose from 10.1?±?0.5 to 18.7?±?0.8 and 21.9?±?1.0?pmol/min/mg protein in DMSO-, CAME- and CAEE-stimulated cells, respectively, similar to insulin (17.7?±?1.2?pmol/min/mg protein), while GLUT4myc translocation increased significantly by 1.70?±?0.18, by 1.73?±?0.18- and by 1.95?±?0.30-fold (relative to DMSO), following insulin, CAME and CAEE stimulation, respectively. CAME and CAEE suppressed hepatocyte G6Pase by 62.0?±?6.9% and 62.7?±?6.0% with IC₅₀ of 45.93 and 22.64?μM, respectively, comparable to insulin (70.7?±?2.3% inhibition). Finally, CAME and CAEE almost abrogated adipogenesis (83.3?±?7.2% and 97.3?±?3.0% at 100?μM; IC₅₀ of 13.8 and 12.9?μM, respectively). The compounds inhibited adipogenic factors C/EBP-β and PPAR-γ and stimulated AMPK activity in the three cell-lines.

Discussion and conclusions: CAME and CAEE exerted antidiabetic activities in insulin-responsive cells through insulin-independent mechanisms involving AMPK and adipogenic factors.     

Inhibition of key enzymes linked to type 2 diabetes by compounds isolated from Aframomum melegueta fruit

Context: The use of Aframomum melegueta K. Schum. (Zingiberaceae) fruit for treatment of diabetes has recently been established in Nigeria. However, compounds responsible for the antidiabetic action have not been identified.

Objective: The present study carried out the bioassay-guided isolation of possible bioactive compounds responsible for the antidiabetic action of A. melegueta fruit.

Materials and methods: The A. melegueta fruit was sequentially extracted using ethyl acetate (EtOAc), ethanol and water, and the most active extract (EtOAc) was subjected to column chromatography on a silica gel column using solvent gradient systems of hexane (HEX):EtOAc and EtOAc:MeOH and the isolation of compounds was guided by α-glycosidase and α-amylase inhibitory activities at various concentrations (30–240?μg/mL).

Results: According to the results, 3 arylalkanes, 6-paradol (1), 6-shogaol (2) and 6-gingerol (3) and a pentacyclic triterpene, oleanolic acid (4) were isolated from A. melegueta fruit. All the compounds exhibited inhibitory effects against α-amylase and α-glucosidase. 6-Gingerol (3) and oleanolic acid (4) showed higher inhibitory activity against α-amylase (IC₅₀: 6-gingerol: 81.78?±?7.79?μM; oleanolic acid: 91.72?±?1.63?μM) and α-glucosidase (IC₅₀: 6-gingerol: 21.55?±?0.45?μM; oleanolic acid: 17.35?±?0.88?μM) compared to the standard drug, acarbose and other isolated compounds. The kinetics of the enzyme action of the compounds showed a noncompetitive mode of inhibition.

Conclusion: The data of this study suggest that the 6-gingerol (3) and oleanolic acid (4) showed higher α-amylase and α-glucosidase inhibitory action and therefore could be responsible for the antidiabetic activity of A. melegueta fruit.     

Evaluation of anti-inflammatory activity and standardisation of hydro-methanol extract of underground tuber of Dioscorea alata

Context The underground edible tuber of Dioscorea alata L. (Dioscoreaceae) is a functional food with high nutritive value and therapeutic potential. The tuber is known to possess anti-inflammatory properties in traditional medicine.

Objective The present study explores the anti-inflammatory activity and standardisation of D. alata tuber hydromethanol extract.

Materials and methods Hydromethanol extract (70%) of D. alata tuber was chemically characterised using HPLC and GC-MS techniques. Murine lymphocytes were cultured for 48?h with six different concentrations (0–80?μg/mL) of the extract. The expression of nitric oxide (NO), TNF-α, COX-1, COX-2, and PGE₂ were evaluated using colorimetric and ELISA methods.

Results Dioscorea alata extract inhibited the expression of NO and TNF-α with an IC₅₀ value of 134.51?±?6.75 and 113.30?±?7.44?μg/mL, respectively. The IC₅₀ values for inhibition of total COX, COX-1, COX-2 activities and PGE₂ level were 41.96?±?3.07, 141.41?±?8.99, 32.50?±?1.69, and 186.34?±?15.36?μg/mL, respectively. Inhibition of PGE₂ level and COX-2 activity was positively correlated (R²?=?0.9393). Gallic acid (GA), 4-hydroxy benzoic acid (4HBA), syringic acid (SYA), p-coumaric acid (PCA), and myricetin (MY) were identified and quantified using HPLC. GC-MS analysis revealed the presence of 13 different phytocompounds such as hexadecanoic acid, methyl stearate, cinnamyl cinnamate, and squalene.

Conclusion The D. alata extract significantly down-regulated the pro-inflammatory signals in a gradual manner compared with control (0?μg/mL). Different bioactive phytocompounds individually possessing anti-inflammatory activities contributed to the overall bioactivity of the D. alata tuber extract.     

Cytotoxic activity and chemical constituents of Anthemis mirheydari

Context The genus Anthemis L. (Asteraceae) comprises about 195 species which are widely used in the pharmaceutical, cosmetic and food industries.

Objective Anthemis mirheydari Iranshar, an endemic plant from Iran, was investigated for its cytotoxic properties and chemical constituents.

Materials and methods The whole parts of the plant (320?g) were extracted by dichloromethane and methanol for four days, successively. The cytotoxic activity of both dichloromethane and methanol extracts were assayed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide colorimetric methods against three human cancer cell lines including LS180, MCF-7 and MOLT-4. Different concentrations (10–100?μg/mL) of the plant extracts were tested to obtain IC₅₀ values. The dichloromethane extract of A. mirheydari was subjected to silica gel-column and thin layer chromatography for purification of its chemical constituents and the isolated compounds were further tested against MOLT-4 cells. The structures of the pure compounds were elucidated using different spectral data including nuclear magnetic resonance and electron impact mass spectra.

Results The IC₅₀ values of the dichloromethane extract were 30.8?±?6.7, 25.2?±?6.5 and 8.6?±?1.1?μg/mL (means?±?standard error) for the above-mentioned cell lines, respectively. Two triterpenoids, taraxasterol (1) and pseudotaraxasterol (2), one sterol, β-sitosterol (3) and one coumarin, 7-methoxycoumarin (4) were isolated from the extract. The IC₅₀ of the mixture of compounds 1 and 2 as well as compounds 3 and 4 were higher (>100?μM) than that reported for the dichloromethane extract against MOLT-4 cells.

Conclusion The dichloromethane extract was the most active one among the tested material.     

Phytochemicals from Dodonaea viscosa and their antioxidant and anticholinesterase activities with structure–activity relationships

Context Dodonaea viscosa (L.) Jacq (Sapindaceae) has been used in traditional medicine as antimalarial, antidiabetic and antibacterial agent, but further investigations are needed.

Objective This study determines the antioxidant and anticholinesterase activities of six compounds (1–6) and two crystals (1A and 3A) isolated from D. viscosa, and discusses their structure–activity relationships.

Materials and methods Antioxidant activity was evaluated using six complementary tests, i.e., β-carotene-linoleic acid; DPPH^?, ABTS^?+, superoxide scavenging, CUPRAC and metal chelating assays. Anticholinesterase activity was performed using the Elman method.

Results Clerodane diterpenoids (1 and 2) and phenolics (3–6) – together with three crystals (1A, 3A and 7A) – were isolated from the aerial parts of D. viscosa. Compound 3A exhibited good antioxidant activity in DPPH (IC₅₀: 27.44?±?1.06?μM), superoxide (28.18?±?1.35% inhibition at 100?μM) and CUPRAC (A_0.5: 35.89?±?0.09?μM) assays. Compound 5 (IC₅₀: 11.02?±?0.02?μM) indicated best activity in ABTS assay, and 6 (IC₅₀: 14.30?±?0.18?μM) in β-carotene-linoleic acid assay. Compounds 1 and 3 were also obtained in the crystal (1A and 3A) form. Both crystals showed antioxidant activity. Furthermore, crystal 3A was more active than 3 in all activity tests. Phenol 6 possessed moderate anticholinesterase activity against acetylcholinesterase and butyrylcholinesterase enzymes (IC₅₀ values: 158.14?±?1.65 and 111.60?±?1.28?μM, respectively).

Discussion and conclusion This is the first report on antioxidant and anticholinesterase activities of compounds 1, 2, 5, 6, 1A and 3A, and characterisation of 7A using XRD. Furthermore, the structure–activity relationships are also discussed in detail for the first time.     

Effects of type 2 diabetes mellitus on the pharmacokinetics of berberine in rats

Context: Berberine is an active alkaloid isolated from Rhizoma coptidis [Coptis chinensis Franch. (Ranunculaceae)] that is widely used for the treatment of diabetes, hyperlipidemia and hypertension. However, the pharmacokinetics of berberine in normal rats and type 2 diabetes mellitus (T2DM) model rats are not clear.

Objective: This study compares the pharmacokinetics of berberine between normal and T2DM model rats.

Materials and methods: The T2DM model rats were fed with high fat diet for 4 weeks, induced by low-dose (30?mg/kg) streptozotocin for 72?h and validated by determining the peripheral blood glucose level. Rats were orally treated with berberine at a dose of 20?mg/kg and then berberine concentration in rat plasma was determined by employing a sensitive and rapid LC-MS/MS method.

Results: The significantly different pharmacokinetic behaviour of berberine was observed between normal and T2DM model rats. When compared with the normal group, C_max, t_1/2 and AUC_(0–t) of berberine were significantly increased in the model group (17.35?±?3.24 vs 34.41?±?4.25?μg/L; 3.95?±?1.27 vs 9.29?±?2.75?h; 151.21?±?23.96 vs 283.81?±?53.92?μg/h/L, respectively). In addition, oral clearance of berberine was significantly decreased in the model group (134.73?±?32.15 vs 62.55?±?16.34?L/h/kg).

Discussion and conclusion: In T2DM model rats, the pharmacokinetic behaviour of berberine was significantly altered, which indicated that berberine dosage should be modified in T2DM patients.     

Mechanism of action of relaxant effect of Agastache mexicana ssp.mexicana essential oil in guinea-pig trachea smooth muscle

Context: Agastache mexicana ssp. mexicana (Kunth) Lint &; Epling (Lamiaceae), popularly known as ‘toronjil morado’, is used in Mexican traditional medicine for the treatment of several diseases such as hypertension, anxiety and respiratory disorders.

Objective: This study investigates the relaxant action mechanism of A. mexicana ssp. mexicana essential oil (AMEO) in guinea-pig isolated trachea model.

Materials and method: AMEO was analyzed by GC/MS. The relaxant effect of AMEO (5–50?μg/mL) was tested in guinea-pig trachea pre-contracted with carbachol (3?×?10?^??⁶?M) or histamine (3?×?10?^??⁵?M) in the presence or absence of glibenclamide (10?^??⁵?M), propranolol (3?×?10?^??⁶?M) or 2′,5′-dideoxyadenosine (10?^??⁵?M). The antagonist effect of AMEO (10–300?μg/mL) against contractions elicited by carbachol (10?^??¹⁵–10?^??³?M), histamine (10?^??¹⁵–10?^??³?M) or calcium (10–300?μg/mL) was evaluated.

Results: Essential oil composition was estragole, d-limonene and linalyl anthranilate. AMEO relaxed the carbachol (EC_50?=_?18.25?±?1.03?μg/mL) and histamine (EC_50?=_?13.3?±?1.02?μg/mL)-induced contractions. The relaxant effect of AMEO was not modified by the presence of propranolol, glibenclamide or 2′,5′-dideoxyadenosine, suggesting that effect of AMEO is not related to β₂-adrenergic receptors, ATP-sensitive potassium channels or adenylate cyclase activation. AMEO was more potent to antagonize histamine (pA₂′?=??1.507?±?0.122) than carbachol (pA₂′?=??2.180?±?0.357). Also, AMEO antagonized the calcium chloride-induced contractions.

Conclusion: The results suggest that relaxant effect of AMEO might be due to blockade of calcium influx in guinea-pig trachea smooth muscle. It is possible that estragole and d-limonene could contribute majority in the relaxant effect of AMEO.     

Effects of glycyrrhizin on the pharmacokinetics of asiatic acid in rats and its potential mechanism

Context: Asiatic acid has been reported to possess a wide range of pharmacological activities.

Objective: This study investigates the effects of glycyrrhizin on the pharmacokinetics of asiatic acid in rats and its potential mechanism.

Materials and methods: The pharmacokinetics of orally administered asiatic acid (20?mg/kg) with or without glycyrrhizin pretreatment (100?mg/kg/day for seven days) were investigated using a LC–MS method. Additionally, the Caco-2 cell transwell model and rat liver microsome incubation systems were used to investigate the potential mechanism of glycyrrhizin’s effects on the pharmacokinetics of asiatic acid.

Results: The results showed that the C_max (221.33?±?21.06 vs. 324.67?±?28.64?ng/mL), AUC_0–inf (496.12?±?109.31 vs. 749.15?±?163.95?μg·h/L) and the t_1/2 (1.21?±?0.27 vs. 2.04?±?0.32?h) of asiatic acid decreased significantly (p?p?Discussion and conclusions: In conclusion, these results indicated that glycyrrhizin could decrease the system exposure of asiatic acid, possibly by inducing the activity of P-gp or CYP450 enzyme.     

Compounds from Sedum caeruleum with antioxidant,anticholinesterase, and antibacterial activities

Context: This is the first study on the phytochemistry, antioxidant, anticholinesterase, and antibacterial activities of Sedum caeruleum L. (Crassulaceae).

Objective: The objective of this study is to isolate the secondary metabolites and determine the antioxidant, anticholinesterase, and antibacterial activities of S. caeruleum.

Materials and methods: Six compounds (1–6) were isolated from the extracts of S. caeruleum and elucidated using UV, 1D-, 2D-NMR, and MS techniques. Antioxidant activity was investigated using DPPH^?, CUPRAC, and ferrous-ions chelating assays. Anticholinesterase activity was determined against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes using the Ellman method. Antibacterial activity was performed according to disc diffusion and minimum inhibitory concentration (MIC) methods.

Results: Isolated compounds were elucidated as ursolic acid (1), daucosterol (2), β-sitosterol-3-O-β-d-galactopyranoside (3), apigenin (4), apigetrin (5), and apiin (6). The butanol extract exhibited highest antioxidant activity in all tests (IC₅₀ value: 28.35?±?1.22?µg/mL in DPPH assay, IC₅₀ value: 40.83?±?2.24?µg/L in metal chelating activity, and IC₅₀ value: 23.52?±?0.44?µg/L in CUPRAC), and the highest BChE inhibitory activity (IC₅₀ value: 36.89?±?0.15?µg/L). Moreover, the chloroform extract mildly inhibited (MIC value: 80?µg/mL) the growth of all the tested bacterial strains.

Discussion and conclusion: Ursolic acid (1), daucosterol (2), β-sitosterol-3-O-β-d-galactopyranoside (3), apigenin (4), apigetrin (5), and apiin (6) were isolated from Sedum caeruleum for the first time. In addition, a correlation was observed between antioxidant and anticholinesterase activities of bioactive ingredients of this plant.     

Immunomodulatory activities of isolated compounds from the root-bark of Cussonia arborea

Context: Cussonia arborea Hochst. ex A. Rich (Araliaceae) is a folk medicine used to treat various diseases. However, there is no report of the root phytochemistry.

Objective: This study isolates and identifies the immunomodulatory compounds from root-bark of C. arborea.

Materials and methods: The methanol extract (18?g) was subjected to repeated column chromatography resulting in isolation of five compounds (1–5). Structure determination was achieved by analysis of their 1?D and 2?D NMR, and mass spectroscopy. The compounds (100–1.0?μg/mL) were examined immunomodulatory for effect on production of reactive oxygen species (ROS) from whole blood phagocytes and on proliferation of T-cells. The compounds cytotoxicity (100–1.0?μg/mL) was evaluated on NIH-3T3 normal fibroblast cells.

Results: Three pentacyclic triterpenoids [3, 23-dihydroxy-12-oleanen-28-oic acid (1), 3β-hydroxylolean-12-en-28-oic (2) and 23-hydoxy-oxo-urs-12-en-28-oic acid (5)], two phytosterols: [stigmasterol (3)] and [3-O-β-d-glucopyranosyl stigmasterol (4)] were all isolated from the methanol soluble extract. All the tested compounds (1–4) were found to be nontoxic on NIH-3T3 cells. Compound 1 and 2 moderately inhibited the production of ROS (IC₅₀?=?24.4?±?4.3 and 37.5?±?0.1?μg/mL, respectively) whereas compound 2 exhibited the highest inhibitory effect (IC₅₀?=?12.6?±?0.4?μg/mL) on proliferation of phytoheamagglutinin (PHA) activated T-cells.

Conclusions: The isolated compounds (1–5) are reported for the first time from this species. In addition, compound 2 with suppressive potential on production of intracellular ROS and proliferation of T-cells could be of immense value in control of autoimmune diseases as well as in immune compromised patients.     

Absorption properties and effects of caffeic acid phenethyl ester and its p-nitro-derivative on P-glycoprotein in Caco-2 cells and rats

Context: Caffeic acid phenethyl ester (CAPE), isolated from honeybee propolis, has pharmacological applications. A synthesized CAPE derivative, p-nitro-caffeic acid phenethyl ester (CAPE-NO₂), showed similar activities with CAPE. The pharmacological activities of CAPE and CAPE-NO₂ are related to their absorption properties.

Objective: To understand the pharmacokinetic profiles of CAPE and CAPE-NO₂ in rats and investigate the absorption mechanisms and effects on P-glycoprotein in Caco-2 cells.

Materials and methods: The pharmacokinetic profiles of CAPE and CAPE-NO₂ were obtained after oral administration (10?mg/kg) to rats. Transport studies of CAPE and CAPE-NO₂ (5, 10, 20?μM) were performed in Caco-2 cell model. P-gp activities were assayed by rhodamine 123 cellular retention. Expression of P-gp was determined after the cells were administrated with CAPE and CAPE-NO₂ (5, 20?μM) for 48 and 72?h.

Results: The AUC_(0?t) of CAPE-NO₂ (3239.9?±?352?ng?×?h/mL) was two-time greater than CAPE (1659.6?±?152?ng?×?h/mL) in rats. The P_app values of CAPE and CAPE-NO₂ were (4.86?±?0.90)?×?10^?6?cm/s and (12.34?±?1.6)?×?10^?6?cm/s, respectively. The accumulation of rhodamine 123 was increased by 1.3- to 1.9-fold and 1.4- to 2.3-fold in CAPE and CAPE-NO₂ groups after 1?h administration, respectively. However, CAPE and CAPE-NO₂ increased the P-gp levels by 2.1- and 1.7-fold, respectively.

Conclusion: The absorption of CAPE-NO₂ can be enhanced in rats and Caco-2 cells compared with CAPE. The two compounds are potential inhibitors of P-gp. The increased P-gp levels generated by CAPE and CAPE-NO₂ played a role as a defense mechanism by limiting intracellular xenobiotic levels.     

Phytochemical screening and evaluation of in vitro antioxidant and antimicrobial activities of the indigenous medicinal plant Albizia odoratissima

Context: Albizia odoratissima (L. f.) Benth has been used in Indian folk medicine to treat numerous inflammatory pathologies, such as leprosy, ulcers, burns and asthma.

Objective: To evaluate the antioxidant and antimicrobial properties of A. odoratissima.

Materials and methods: Dried leaves of A. odoratissima were extracted in organic solvents (hexane, chloroform, ethyl acetate, and methanol). The total phenolic content (TPC) and total flavonoid content (TFC) were determined using the Folin-Ciocalteu and aluminum chloride colorimetric methods, respectively. The antioxidant activity was examined using 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydrogen peroxide (H₂O₂), 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt (ABTS), and ferric reducing antioxidant power (FRAP) assays. The antibacterial activity was examined using minimum inhibitory concentration (MIC) and the minimum bacterial concentration (MBC), determined by broth microdilution method against Gram-negative bacteria (Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, and Proteus vulgaris) and Gram-positive bacterium (Staphylococcus aureus).

Results: The TPC ranged from 4.40?±?1.06 to 1166.66?±?31.85?mg GAE/g of dry weight (DW), and the TFC ranged from 48.35?±?3.62 to 109.74?±?1.84?mg QE/g of DW. The IC₅₀ values of the ethyl acetate extract for DPPH, ABTS, and H₂O₂ were 10.96?±?0.40, 4.35?±?0.07, and 163.82?±?1.52?μg/mL, respectively. Both methanol and ethyl acetate extracts demonstrated effective antibacterial activity with MICs and MBCs values ranging 136–546?μg/mL and 273–1093?μg/mL, respectively, against the tested pathogenic species.

Conclusions: The leaves of A. odoratissima showed potent free radical scavenging property and antimicrobial activity.     

Effects of Ginkgo leaf tablets on the pharmacokinetics of losartan and its metabolite EXP3174 in rats and its mechanism

Context: Ginkgo leaf tablets (GLTs) and losartan are often simultaneously used for the treatment of hypertension in Chinese clinics. However, the herb–drug interaction between GLT and losartan is still unknown.

Objective: This study investigates the effects of GLT on the pharmacokinetics of losartan and its metabolite EXP3174 in rats and its potential mechanism.

Materials and methods: The pharmacokinetic profiles of losartan and EXP3174 of orally administered losartan (10?mg/kg) with or without GLT pretreatment (80?mg/kg/day for 10?days) in Sprague–Dawley rats were determined. In vitro, the effects of GLT on the metabolic stability of losartan were investigated with rat liver microsomes.

Results: The C_max (1.22?±?0.25 vs 1.85?±?0.37?μg/mL) and the AUC_(0–t) (6.99?±?1.05 vs 11.94?±?1.79?mg·h/L) of losartan increased significantly (p?C_max (1.05?±?0.19 vs 0.72?±?0.12?μg/mL) of EXP3174 decreased significantly (p?t_1/2 of losartan was prolonged significantly from 3.94?±?0.62 to 4.75?±?0.52?h (p?Discussion and conclusions: The results indicate that GLT might increase the plasma concentration of losartan and decrease the concentration of EXP3174 through inhibiting the metabolism of losartan.     

In Vitro antileishmania activity of sesquiterpene-rich essential oils from Nectandra species

Context: New antileishmanias are needed because of toxicity, high cost and resistance problems associated with available drugs. Nectandra (Lauraceae) produces several classes of compounds but its essential oil has not previously been reported to have antileishmania activity.

Objective: We evaluated the cytotoxicity and antileishmania activity of essential oils from Nectandra amazonum Nees, N. gardneri Meisn., N. hihua (Ruiz &; Pav.) Rohwer and N. megapotamica (Spreng.) Mez.

Materials and methods: Nectandra oils were extracted from stem bark/leaves by hydrodistillation and compounds were identified by GC-MS. Oils were tested against Leishmania infantum and L. amazonensis intracellular amastigotes and nitric oxide production was evaluated. Cytotoxicity was achieved on NIH/3T3 and J774.A1 cells for the selectivity index (SI).

Results and discussion: Nectandra gardneri was active against L. infantum and L. amazonensis (IC₅₀?= 2.7?±?1.3/2.1?±?1.06?μg/mL) and contained 85.4% sesquiterpenes, of which 58.2% was intermediol. Besides low cytotoxicity (SI >11.3), N. gardneri induced a significant increase in NO production by L. infantum-infected macrophages. Nectandra hihua had the best activity on L. infantum amastigotes (IC₅₀?= 0.2?±?1.1?μg/mL). This oil was 89.0% sesquiterpenes, with 28.1% bicyclogermacrene. The two specimens of N. megapotamica had different activities on amastigotes. The one richer in sesquiterpenes (49.9%) was active against both species (IC₅₀?= 12.5?±?1.4/21.3?±?1.2) and had phenylpropanoid E-asarone as the main compound (42.4%). Nectandra amazonum showed moderate activity on both the species (IC₅₀?= 31.9?±?2.0/22.1?±?1.3?μg/mL) and low selectivity (0.9?2.6), probably due to the major presence of β-caryophyllene (28.5%).

Conclusions: Our data identify compounds that can now be isolated and used for the development of new antileishmanias.