Antimicrobial activity of the methanolic extract and compounds from Morus mesozygia stem bark

Aim of the study

This study was aimed at investigating the antimicrobial activity of the methanolic extract (MMB) and compounds isolated from the stem bark of Morus mesozygia, namely 3β-acetoxyurs-12-en-11-one (1), moracin Q (2), moracin T (3), artocarpesin (4), cycloartocarpesin (5), moracin R (6), moracin U (8), moracin C (9), and moracin M (10).

Materials and Methods

The liquid microdilution assay was used in the determination of the minimal inhibitory concentration (MIC) and the minimal microbicidal concentration (MMC), against nine bacterial and two fungal species.

Results

The results of the MIC determination showed that the compounds 3, 4, 8 and 9 were able to prevent the growth of all tested microbial species. All other samples showed selective activities. Their inhibitory effects were noted on 90.9% studied organisms for the crude extract, 81.8% for compound 6, 72.7% for compound 10, 63.6% for compound 1, 54.5% for compound 5, and 45.5% for compound 2. The lowest MIC value of 39 μg/ml was obtained with the crude extract against Escherichia coli. The corresponding value for compounds (5 μg/ml) was registered with compound 9 on Shigella dysenteriae and compound 3 on E. coli, S. dysenteriae, Pseudomonas aeruginosa, Salmonella typhi and Bacillus cereus. The lowest MIC value (39 μg/ml) observed with the crude extract (on E. coli) was only eightfold greater than that of gentamycin used as reference antibiotic (RA) while the corresponding value (5 μg/ml) recorded with compounds 3 and 9 was equal to that of RA on the corresponding microorganisms.

Conclusions

The obtained results highlighted the interesting antimicrobial potency of M. mesozygia as well as that of the studied compounds, and provided scientific basis for the traditional use of this species.     

Bioactive styryllactones and alkaloid from flowers of Goniothalamus laoticus

Ethnopharmacological relevance

Goniothalamus laoticus (Annonaceae) is being used traditionally as a tonic and a febrifuge by the local people in the northeastern part of Thailand.

Aim of study

To investigate the Thai medicinal plant, Goniothalamus laoticus, for antiplasmodial, antimycobacterial and cytotoxicity activities.

Materials and methods

The flowers extracts of Goniothalamus laoticus were isolated by chromatographic techniques. Structures of isolated compounds were identified by spectroscopic methods. The antiplasmodial, antimycobacterial and cytotoxicity evaluation of styryllactone derivatives and alkaloid were also performed.

Results

Ten compounds, cinnamic acid (1); dihydrochrysine (2); β-sitosterol (3); six styryllactones, (+)-3-acetylaltholactone (4), goniotriol (5), (+)-altholactone (6), (+)-goniofufurone (7), 9-deoxygoniopypyrone (8), howiinin A (9); and an aporphine alkaloid; (−)-nordicentrine (10) were isolated from flowers of Goniothalamus laoticus. Among these, compounds 1, 3–5, 8–10 are first isolated from the Goniothalamus laoticus. Besides, compound 10 is the first report from the Goniothalamus genus. The isolated compounds were evaluated in antiplasmodial, antimycobacterial and anticancer cell lines tests. Compounds 4–6 and 10 exhibited antiplasmodial activity against Plasmodium falciparum (IC₅₀ 2.6, 7.9, 2.6 and 0.3 μg/mL, respectively), while 5, 6, 9 and 10 showed antimycobacterial activity against Mycobacterium tuberculosis (MIC 100, 6.25, 6.25 and 12.5 μg/mL, respectively). In addition, compounds 4–10 showed cytotoxicity against cancer cells, KB, BC1, NCI-H187, and MCF-7 with IC₅₀ ranging from 0.4 to 22.7 μg/mL.

Conclusion

This finding showed that the styryllactone derivatives and alkaloid isolated from the flowers of Goniothalamus laoticus exhibited antiplasmodial activity against Plasmodium falciparum, antimycobacterail against Mycobacterium tuberculosis and cytotoxicity against four cancer cell lines.     

In vitro activity of Tridax procumbens against promastigotes of Leishmania mexicana

Ethnopharmacological relevance

Tridax procumbens is an active herb against leishmaniasis.

Aim of the study

Leishmaniasis is a group of diseases caused by Leishmania protozoa. We investigated the antileishmanial activity of Tridax procumbens extracts and a pure compound against promastigotes of Leishmania mexicana, the causative agent of cutaneous leishmaniasis in the New World.

Materials and methods

Extracts and (3S)-16,17-didehydrofalcarinol (1) were obtained by chromatographic methods from Tridax procumbens, and the latter identified by spectroscopic analysis. The effect of these extracts and 1 on the growth inhibition of promastigotes of Leishmania mexicana was evaluated. In order to test the safety of extracts and 1, mammalian cells were treated with them, and cell viability was assessed using trypan blue and MTT.

Results

We demonstrated that extracts of Tridax procumbens and 1 showed a pronounced activity against Leishmania mexicana. The methanol extract inhibited promastigotes growth of Leishmania mexicana with a 50% inhibitory concentration (IC₅₀) of 3 μg/ml, while oxylipin 1 exhibited the highest inhibition at IC₅₀ = 0.478 μg/ml.

Conclusions

In this study we report the biological activity of extracts and (3S)-16,17-didehydrofalcarinol (1), obtained from Tridax procumbens, on the promastigote form of Leishmania mexicana, with no effect upon mammalian cells.     

Isolation and identification of antibacterial and cytotoxic compounds from the leaves of Muntingia calabura L.

Ethnopharmacological relevance

Muntingia calabura (Elaeocarpaceae) is one of the most common roadside trees in Malaysia. Its leaves, barks, flowers and roots have been used as a folk remedy for the treatment of fever, incipient cold, liver disease, as well as an antiseptic agent in Southeast Asia. The aim of this study is to isolate and identify the antibacterial and cytotoxic compounds from the leaves of Muntingia calabura L.

Materials and methods

Antibacterial and cytotoxic activities were determined by micro-broth dilution and MTT assays, respectively. Seven fractions (F1–F7), three flavones and a chalcone were isolated from the active EtOAc extract using bioassay-guided screening. The structures of four compounds were elucidated by spectroscopic methods and compared with published data. The compounds were further tested for their antibacterial and cytotoxic activities.

Results

Three flavones and a chalcone [5,7-dihydroxy-3,8-dimethoxyflavone (1), 2′,4′-dihydroxychalcone (2), 5-hydroxy-3,7-dimethoxyflavone (3) and 3,5,7-trihydroxy-8-methoxyflavone (4)] were isolated from the active fraction F5 of EtOAc extract. Compounds 1 and 3 were isolated for the first time from Muntingia calabura L. Antibacterial activity indicates that compound 2 exhibited the most significant activity with MIC value of 50 μg/mL and 100 μg/mL against MSSA and MRSA, respectively. Cytotoxic activity indicates that compounds 2 and 3 exhibited very strong activity against HL60 with IC₅₀ values of 3.43 μg/mL and 3.34 μg/mL, respectively.

Conclusion

The antibacterial activity of the leaves of Muntingia calabura L. is ascribable to the active compound 2 while the cytotoxic activity is ascribable to the active compounds 2 and 3.     

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.     

Antimicrobial activity of the crude extract,fractions and compounds from stem bark of Ficus ovata (Moraceae)

Aim of the study

This study was designed to investigate the antimicrobial activities of the methanol extracts from the stem bark of Ficus ovata (FOB), fractions (FOB1–6) and compounds isolated following bio-guided fractionation [3-friedelanone (1), taraxeryl acetate (2), betulinic acid (3), oleanoïc acid (4), 2-hydroxyisoprunetin (5), 6,7-(2-isopropenyl furo)-5,2,4-trihydroxyisoflavone (6), Cajanin (7) and protocatechuic acid (8)].

Materials and Methods

The micro-dilution method was used for the determination of the minimal inhibition concentration (MIC) and the minimal microbicidal concentration (MMC) against fungi (two species), Gram-positive (three species) and Gram-negative bacteria (five species).

Results

The results of the MIC determinations indicated that the crude extract (FOB), fractions FOB2 and FOB4 as well as compound 5 were active on the entire studied organisms. Other samples showed selective activity, fractions FOB1, FOB3 and FOB5 being active against 50% of the tested microbial species while FOB6 was active on 40%. Compounds 8, 6, 2 and 7 prevented the growth of 80%, 70%, 50% and 20% of the organisms respectively. The lowest MIC value (156g/ml) observed with the crude extract was recorded on Streptococcus faecalis, Candida albicans and Microsporum audouinii. The corresponding value for fractions (39 μg/ml) was noted with FOB4 against Staphylococcus aureus, while that of the tested compounds (10 μg/ml) was observed with compound 8 on Microsporum audouinii. The results of the MMC determination suggested that the cidal effect of most of the tested samples on the studied microorganisms could be expected.

Conclusions

The overall results provided evidence that the studied plant extract, as well as some of the isolated compounds might be potential sources of new antimicrobial drug.     

In vitro estrogenic activity of Asplenium trichomanes L. extracts and isolated compounds

Ethnopharmacological relevance

Asplenium trichomanes was used as an expectorant, anti-cough remedy, laxative, emmenagogue, abortifacient and for irregular menses.

Aim of the study

To investigate the in vitro estrogenic activity of Asplenium trichomanes extracts and isolated compounds and their ability to activate ERα and ERβ.

Materials and methods

Leaves infusion (IF), decoction (DC) and methanol extract (ME) were prepared. MCF7/EREluc cell line which expresses endogenous ERα, and SK-NBE cells transiently transfected with the estrogen receptors (ERα and ERβ) were used for the estrogenic activity assays. Phytochemical investigations were performed (CC, HPLC, etc.) and structure of isolated compounds were achieved on the basis of 1D and 2D NMR techniques and HR-MS spectrometry.

Results

IF and ME were active in our MCF7 model; selectivity for the ERβ receptor was observed in the SK-NBE test. Two new phenol derivatives, 4-vinyl-phenol-1-O-[α-l-rhamno(1 → 6)-β-d-glucopyranosyde] (1) and kaempferol-3-O-α-[2′acetyl]-arabinofuranosyl-7-O-α-l-rhamnopyranoside (2) were isolated with six known compounds (3–8). Compounds 2–4, 7 and 8 showed selectivity for the activation of the ERβ receptor although with a moderate activity compared with 17-β-estradiol.

Conclusion

Further investigations about the estrogenic effects of this plant are needed but our data can, at least in part, explain some of its traditional use as emmeagogue.     

Sedative activity of hexane extract of Keampferia galanga L. and its active compounds

Ethnopharmacological relevance

It is well known that fragrance impacts behaviors and autonomic functions, and is increasingly used as relaxant, carminative, as well as sedative in aromatherapy. Kaempferia galanga L. is one of the popular traditional aromatic medicinal plants used in tropics and subtropics of Asia including China, Japan and Indochina.

Aim of the study

The aim of present study was to investigate sedative effects of hexane extract of Kaempferia galanga L.and 2 active aromatic compounds (compound 1: ethyl trans-p-methoxycinnamate and compound 2: ethyl cinnamate ) included in the extyract by means of inhalation in mice.

Materials and methods

Sedative activity was assessed by inhalation of the hexane extract and two major aromatic compounds.

Results

Inhalation of hexane extract at the doses of 1.5 and 10 mg showed significant reduction of locomotor activity, indicating considerable sedative and relaxant effects. Compound 1 and 2 were proved to possess sedative effects at 0.0014 mg and 0.0012 mg respectively.

Conclusions

These results suggest the promising application of Kaempferia galanga L. and its constituents in aromatherapy.     

Antimicrobial activities of methanol extract and compounds from stem bark of Vismia rubescens

Ethnopharmacological relevance

The plant, Vismia rubescens (Guttiferae) is popularly used in Cameroon and in several parts of Africa as febrifugal and for the treatment of various microbial infections (skin diseases, diarrhoea and venereal diseases).

Aim of the study

This study was mapped out to evaluate the antimicrobial activities of the methanol extract and compounds from the stem bark of Vismia rubescens.

Materials and methods

Structures of the compounds obtained after column chromatography of the methanol-soluble fraction were determined by spectroscopy and in comparison with published data. The broth micro-dilution method was used to evaluate the antimicrobial activities against three bacteria species (Salmonella typhi, Stahylococcus aureus and Pseudomonas aeruginosa) and four yeast species (Candida albicans, Candida tropicalis, Candida parapsilosis and Cryptococcus neoformans).

Results

Chemical analysis of the methanol extract from the stem bark of Vismia rubescens yielded five known compounds 1,4,8-trihydroxyxanthone (1), 1,7-dihydroxyxanthone (2), physcion (3), friedelin (4) and friedelanol (5). The crude extract and compounds 1, 2 and 3 exhibited both antibacterial and antifungal activities that varied between the microbial species (MIC = 3.12–1000 μg/ml). Compounds 2 and 3 were the most active (MIC = 3.12–100 μg/ml) while Stahylococcus aureus and Pseudomonas aeruginosa were sensitive to all the tested compounds. The antimicrobial activity of this plant as well as that of compounds 1 and 2 is being reported here for the first time.

Conclusion

These results provide promising baseline information for the potential use of this plant as well as some of the isolated compounds in the treatment of skin diseases and diarrhoea.     

Monoterpene bisindole alkaloids,from the African medicinal plant Tabernaemontana elegans, induce apoptosis in HCT116 human colon carcinoma cells

Ethnopharmacological relevance

Tabernaemontana elegans is a medicinal plant used in African traditional medicine to treat several ailments including cancer. The aims of the present study were to identify anti-cancer compounds, namely apoptosis inducers, from Tabernaemontana elegans, and hence to validate its usage in traditional medicine.

Methods and materials

Six alkaloids, including four monomeric indole (1–3, and 6) and two bisindole (4 and 5) alkaloids, were isolated from the methanolic extract of Tabernaemontana elegans roots. The structures of these compounds were characterized by 1D and 2D NMR spectroscopic and mass spectrometric data. Compounds 1−6 along with compound 7, previously isolated from the leaves of the same species, were evaluated for in vitro cytotoxicity against HCT116 human colon carcinoma cells by the MTS metabolism assay. The cytotoxicity of the most promising compounds was corroborated by Guava-ViaCount flow cytometry assays. Selected compounds were next studied for apoptosis induction activity in HCT116 cells, by evaluation of nuclear morphology following Hoechst staining, and by caspase-3 like activity assays.

Results

Among the tested compounds (1−7), the bisindole alkaloids tabernaelegantine C (4) and tabernaelegantinine B (5) were found to be cytotoxic to HCT116 cells at 20 µM, with compound 5 being more cytotoxic than the positive control 5-Fluorouracil (5-FU), at a similar dose. In fact, even at 0.5 µM, compound 5 was more potent than 5-FU. Compounds 4 and 5 induced characteristic patterns of apoptosis in HCT116 cancer cells including, cell shrinkage, condensation, fragmentation of the nucleus, blebbing of the plasma membrane and chromatin condensation. Further, general caspase-3-like activity was increased in cells exposed to compounds 4 and 5, corroborating the nuclear morphology evaluation assays.

Conclusions

Bisindole alkaloids tabernaelegantine C (4) and tabernaelegantinine B (5) were characterized as potent apoptosis inducers in HCT116 human colon carcinoma cells and as possible lead/scaffolds for the development of anti-cancer drugs. This study substantiates the usage of Tabernaemontana elegans in traditional medicine to treat cancer.     

Zanthoxylum capense constituents with antimycobacterial activity against Mycobacterium tuberculosis in vitro and ex vivo within human macrophages

Ethnopharmacological relevance

Zanthoxylum capense Thunb. (Rutaceae) is a medicinal plant traditionally used in Mozambique to treat tuberculosis.

Aims of the study

The main aim of the study was to find antimycobacterial lead compounds from Zanthoxylum capense. Another goal was to provide scientific validation for the use of this plant in traditional medicine.

Methods and materials

By bioassay-guided fractionation, 16 compounds were isolated and screened for their in vitro antimycobacterial activity against two different strains of Mycobacterium tuberculosis. Their in vitro cytotoxicity to human THP-1 macrophages was also assessed. The compounds with favourable selectivity index values (SI>10) were further investigated for their ability to inhibit the growth of Mycobacterium tuberculosis H37Rv in an intracellular macrophage model of infection.

Results

The best results were obtained for a benzophenanthridine alkaloid, decarine (1), and an N-isobutylamide, N-isobutyl-(2E,4E)-2,4-tetradecadienamide (15), which showed high activity against Mycobacterium tuberculosis H37Rv (MIC of 1.6 μg/ml), and a low macrophage cytotoxicity (IC₅₀>60 μg/ml), indicating considerable selective activity. The benzophenanthridine alkaloid 6-acetonyldihydronitidine (6) revealed cytotoxicity (IC₅₀ 1.7 μg/ml), despite the determined MIC of 6.2–12.5 μg/ml. In infected macrophages, decarine (1) was able to reduce bacterial survival by almost two log units at a concentration of 6.2 μg/ml 5 days post-drug exposure. Compound 15 exhibited an intermediate activity at drug concentrations ranging from 6.2 to 25 μg/ml.

Conclusions

The high antimycobacterial activity of decarine found, both in vitro and ex vivo against mycobacteria, and the low cytotoxicity towards human macrophages indicate that it may be valuable as a lead scaffold for the development of anti-TB drugs.     

Antitubercular constituents from Premna odorata Blanco

Ethnopharmacological relevance

Premna odorata Blanco (Lamiaceae) is a medicinal plant traditionally used in Albay Province, in southeastern Luzon, Philippines to treat tuberculosis. This study aimed to determine the antitubercular property of the crude extract and sub-extracts of the leaves, and to isolate the bioactive principles from the active fractions.

Materials and methods

Through extraction, solvent polarity-based fractionation and silica gel chromatography purification of the DCM sub-extract, compound mixtures from the bioactive fractions were isolated and screened for their in vitro antimycobacterial activity against Mycobacterium tuberculosis H₃₇Rv using the colorimetric Microplate Alamar Blue assay (MABA).

Results

The crude methanolic extract and sub-extracts showed poor inhibitory activity against Mycobacterium tuberculosis H₃₇Rv (MIC≥128 µg/mL). However, increased inhibitory potency was observed for fractions eluted from the DCM sub-extract (MIC=54 to 120 µg/mL). Further purification of the most active fraction (MIC=54 µg/mL) led to the isolation of a 1-heneicosyl formate (1), 4:1 mixture of β-sitosterol (2), stigmasterol (3) and diosmetin (4), which were identified through GC–MS analysis (with dereplication) and NMR experiments. The MIC of compound 1 was 8 µg/mL.

Conclusions

The results of this study provide scientific basis for the traditional use of Premna odorata as treatment for tuberculosis.     

Anti-inflammatory mechanism of Kaempferia parviflora in murine macrophage cells (RAW 264.7) and in experimental animals

Ethnopharmacological relevance

The rhizomes of Kaempferia parviflora Wall. ex Baker have been used in Thailand for treatment of gout, apthous ulcer, peptic ulcer and abscesses.

Aim of the study

In our previous study, the crude ethanol extract of Kaempferia parviflora and its compound (5, 5-hydroxy-3,7,3′,4′-tetramethoxyflavone), was reported to show nitric oxide (NO) inhibition in RAW 264.7 cells. The present study is thus investigated the anti-inflammatory mechanism of Kaempferia parviflora extract and compound 5 against inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) mRNA expressions.

Materials and methods

The extract of Kaempferia parviflora and its compound were tested against NO and prostaglandin E₂ (PGE₂) releases using RAW264.7 cells as well as studied on anti-inflammatory activity in carrageenan-induced rat paw edema and acute toxicity in mice.

Results

The results revealed that the ethanol extract of Kaempferia parviflora markedly inhibited PGE₂ release with an IC₅₀ value of 9.2 μg/ml. This plant extract and compound 5 also suppressed mRNA expression of iNOS in dose-dependent manners, whereas COX-2 mRNA expression was partly affected. According to the in vivo study, chloroform and hexane fractions greater decreased rat paw edema than ethanol, ethyl acetate and water fractions.

Conclusion

The mechanisms for anti-inflammatory activity of Kaempferia parviflora and compound 5 are mainly due to the inhibition of iNOS mRNA expression but partly through that of COX-2 mRNA.     

Antinociceptive and anti-inflammatory kaempferol glycosides from Sedum dendroideum

Aim of the study

To identify the compounds responsible for the antinociceptive and anti-inflammatory effects previously described for Sedum dendroideum, through bioassay-guided fractionation procedures.

Materials and methods

Antinociceptive activity was evaluated through mouse acetic acid-induced writhing model. The anti-inflammatory activity was assessed through croton oil-induced mouse ear oedema and carrageenan-induced peritonitis.

Results

The Sedum dendroideum juice afforded seven known flavonoids identified with basis on NMR data. The oral administration of the major kaempferol glycosides kaempferitrin [1] (17.29 μmol/kg), kaempferol 3-O-β-glucopyranoside-7-O-α-rhamnopyranoside [2] (16.82 μmol/kg), kaempferol 3-O-neohesperidoside-7-O-α-rhamnopyranoside [3] (13.50 μmol/kg) or α-rhamnoisorobin [5] (23.13 μmol/kg) inhibited by 47.3%, 25.7%, 60.2% and 58.0%, respectively, the acetic acid-induced nociception (indomethacin: 27.95 μmol/kg, p.o.; 68.9%). Flavonoids 1, 2, 3 or 5, at the same doses, reduced by 39.5%, 46.5%, 35.6% and 33.3%, respectively, the croton oil-induced oedema (dexamethasone: 5.09 μmol/kg, s.c.; 83.7%) and impaired leukocyte migration by 42.9%, 46.3%, 50.4% and 49.6%, respectively (dexamethasone: 5.09 μmol/kg, s.c.; 66.1%).

Conclusions

Our findings show that the major kaempferol glycosides may account for the renowned medicinal use of Sedum dendroideum against pain and inflammatory troubles.     

The constituents of Cibotium barometz and their permeability in the human Caco-2 monolayer cell model

Ethnopharmacological relevance

Cibotium barometz (L.) J. Sm. (Dicksoniaceae) has been traditionally used as anti-inflammatory and anodyne.

Aim of the study

To investigate the constituents in the rhizomes of Cibotium barometz, and evaluate their permeability in the human Caco-2 model.

Materials and methods

The rhizomes extracts of Cibotium barometz were isolated by chromatographic techniques. Structures of isolated compounds were identified by spectroscopic methods. The permeability of the main constituents was evaluated using human Caco-2 cell monolayer as a model system.

Results

Three unusual sesquiterpenes having 1-indanone nucleus (1, 3 and 4) and an unusual orthoester spiropyranosyl derivative of protocatechuic acid (2) were isolated from the rhizomes of Cibotium barometz. Among these, the bilateral permeation of 1, 3 and 4 in Caco-2 model was examined. The apparent permeability coefficients (P_app) of 1 was identical with those of propranolol, which is often used as reference standard of high permeability. The P_app values of 3 and 4 were in agreement with those of atenolol, which is often used as reference standard of poor permeability. The permeation rates of 1, 3 and 4 increased linearly as a function of time up to 180 min and with the concentration within the test range of 25–200 μM.

Conclusions

This is the first report on the presence of compounds 2 and 3 in this plant and 4 was a new compound. Compound 1 is assigned for a well-absorbed, and 2 and 3 are assigned for the poorly absorbed compounds in human intestine. A passive diffusion mechanism for transport of 1, 3 and 4 in Caco-2 model was proposed. The results provided some useful information for predicting the oral bioavailability of 1, 3 and 4.     

Tumoral cytotoxic and antioxidative phenylpropanoid glycosides in Smilax riparia A. DC

Ethnopharmacological relevance

Smilax riparia A. DC., known as “Niu-Wei-Cai” in China, is distributed through the south and middle of China. The roots and rhizomes of Smilax riparia have been used not only as traditional Chinese medicines (TCMs) for the treatment of bronchitis, lumbago of renal asthenia, traumatic injury, asthenia edema, and cancer but also as edible wild herbs in some areas of China.

Aim of the study

To identify the phytochemicals in the roots and rhizomes of Smilax riparia and to investigate their antioxidant activities and cytotoxicities toward several tumor cell lines.

Materials and methods

Four fractions and five phenylpropanoid glycosides were obtained from roots and rhizomes of Smilax riparia under bioassay-guided screenings. The structures of five compounds were elucidated by spectroscopic methods and compared with published data. We evaluated their antioxidant activities and their cytotoxicities on five cancer cell lines: human promyelocytic leukemia (HL-60), human hepatocellular carcinoma (SMMC-7721), human lung cancer (A-549), human breast cancer (MCF-7), and human colon cancer (SW480).

Results

Of the five glycosides, one new compound (3, smilaside P) was isolated from an EtOAc fraction. Compound 1 was cytotoxic toward HL-60, SMMC-7721, A-549, MCF-7, and SW480 (IC₅₀ 2.70, 3.80, 11.91, 3.79, and 3.93 μM, respectively). Moreover, compounds 1–3 showed moderate scavenging activities against the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical (IC₅₀ 339.58, 330.66, 314.49 μM, respectively).

Conclusions

Five phenylpropanoid glycosides were reported for the first time from this TCM. Each was studied, as observed here for the first time, in the cytotoxic experiments toward HL-60, SMMC-7721, and SW480 cell lines. Compound 1, bearing three feruloyl groups and three acetyl groups, had the greatest cytotoxicity toward the five tumor cell lines. Compounds 1–3 showed moderate antioxidant activities. All results reflect that compounds 1–3 are cytotoxic for a wide variety of cancer cell lines of differing tissue origins and that the cytotoxicities of these compounds may be related to their antioxidant activities.     

Isolation of jacaranone,a sedative constituent extracted from the flowers of the Mexican tree Ternstroemia pringlei

Ethnopharmacological relevance

Ternstroemia pringlei represents one of the most widely employed and commercially exploited medicinal plant in Mexico, used popularly as a tranquilizer and for the treatment of insomnia.

Aim of the study

To investigate the sedative constituents of the plant through a bio-guided fractionation of extracts derived from calyx and fruits.

Materials and methods

Crude extracts with different polarities (CHCl₃, AcOEt, MeOH, aqueous) were prepared and subjected to chromatographic fractionation, leading to the isolation of the sedative compound (1) from the MeOH crude extract. The identity of 1 was unequivocally established by means of 1D and 2D NMR spectroscopic analysis. The sleeping time induced by sodium pentobarbital and the elevated plus-maze models were performed on mice to determine the sedative and anxiolytic activities, respectively. Bioactivity was also investigated though in vitro GABA release experiments using mice brain slices.

Results

The sedative compound was established as jacaranone (1), and its effect was clearly demonstrated through a dose-dependent response analysis (ED₅₀ = 25 mg/kg mouse weight). When tested in the elevated plus-maze model, none of the extracts from Ternstroemia pringlei displayed anxiolytic activity. GABA release experiments showed that the MeOH and aqueous crude extracts released this neurotransmitter at a ratio of 217 and 179 pmol/g protein, respectively, evidencing the presence of other bioactive constituents in the extracts apart of 1, whose activity was absent in this model.

Conclusions

Although 1 has been isolated and identified in a number of plant species, this is the first time that its sedative effect has been demonstrated. No previous record exists of other sedative compounds having been isolated from Ternstroemia pringlei.     

Anti-cancer activity of compounds from Bauhinia strychnifolia stem

Ethnopharmacological relevance

The stem and root of Bauhinia strychnifolia Craib (Fabaceae family) have been traditionally used in Thailand to treat fever, alcoholic toxication, allergy and cancer. An EtOH extract of Bauhinia strychnifolia showed good inhibitory activity against several cancer cell lines including HT-29, HeLa, MCF-7 and KB. As there has been no previous reports on chemical constituents of Bauhinia strychnifolia, this study is aimed to isolate the pure compounds with anti-cancer activity.

Materials and methods

Five pure compounds were isolated from EtOH extract of Bauhinia strychnifolia stem using silica gel, dianion HP-20 and sephadex LH-20 column chromatography and were tested for their cytotoxic effects against HT-29, HeLa, MCF-7 and KB cell lines using the Sulforhodamine B (SRB) assay.

Results

Among five compounds, 3,5,7,3′,5′-pentahydroxyflavanonol-3-O-α-l-rhamnopyranoside (2) possessed very potent activity against KB (IC₅₀=0.00054 μg/mL), HT-29 (IC₅₀=0.00217 μg/mL), MCF-7 (IC₅₀=0.0585 μg/mL) and HeLa cells (IC₅₀=0.0692 μg/mL). 3,5,7-Trihydroxychromone-3-O-α-l-rhamnopyranoside (3) also showed good activity against HT-29 (IC₅₀=0.02366 μg/mL), KB (IC₅₀=0.0412 μg/mL) and MCF-7 (IC₅₀=0.297 μg/mL), respectively. The activity of 2 (IC₅₀=0.00054 μg/mL) against KB cell was ten times higher than that of the positive control, Camptothecin (anti-cancer drug, IC₅₀=0.0057 μg/mL). All compounds did not show any cytotoxicity with normal cells at the concentration of 1 μg/mL.

Conclusion

This is the first report of compounds 2 and 3 on anti-cancer activity and based on the anti-cancer activity of extracts and pure compounds isolated from Bauhinia strychnifolia stem, it might be suggested that this plant could be useful for treatment of cancer.     

Non-toxic melanin production inhibitors from Garcinia livingstonei (Clusiaceae)

Ethnopharmacological relevance

The stem bark of Garcinia livingstonei is used traditionally as a skin lightening agent.

Aim of the study

To isolate and identify compounds responsible for the observed skin lightening activity of Garcinia livingstonei and to evaluate their cytotoxicity.

Materials and methods

Constituents of the stem bark and fruits of Garcinia livingstonei were isolated using chromatographic techniques and structures were determined using 1D and 2D NMR and MS analysis. MeWo cells were used to evaluate the cytotoxicity and impact on melanin levels of extracts and compounds isolated, in vitro.

Results

Twelve known compounds, morelloflavone (1), morelloflavone-7″-sulphate (2), guttiferone A (3), sargaol (4), isojacareubin (5), 6-deoxyisojacareubin (6) and in addition to the common triterpenoids, betulin, betulin aldehyde, lupeol, lupenone, euphol and stigmasterol were isolated in this investigation. Morelloflavone, morelloflavone-7″-sulphate and sargaol, were found to be considerably less cytotoxic and more effective as skin lightening agents than hydroquinone.

Conclusions

A range of compounds was isolated from the stem bark and fruit of Garcinia livingstonei. Although the bark extract contained the cytotoxic guttiferone A, it was found to be less toxic than hydroquinone, and morelloflavone, the 7″-sulphate derivative and sargaol show potential for development as depigmentation/skin lightening agents.     

Antiangiogenic activity of Tripterygium wilfordii and its terpenoids

Ethnopharmacological relevance

Tripterygium wilfordii Hook. f. (Celastraceae) has been traditionally used as folk medicine for centuries in China for the treatment of immune-inflammatory diseases.

Aim of the study

This study aimed to assess the antiangiogenic activities which support the therapeutic use of Tripterygium wilfordii and its terpenoids for angiogenesis disease such as cancer.

Materials and methods

The ethanol extract of Tripterygium wilfordii and subsequent fractions were evaluated on an in vivo antiangiogenic zebrafish embryo model.

Results

Three antiangiogenic terpenoids were isolated by bioassay-guided purification, namely, celastrol (4), cangoronine (5) and triptolide (7). Among them, triptolide manifested the most potent antiangiogenic activity against vessel formation by nearly 50% at 1.2 μM. Semi-quantitative RT-PCR analysis revealed that triptolide dose- and time-dependently reduced the mRNA expression of angiopoietin (angpt)2 and tie2 in zebrafish, indicating the involvement of angpt2/tie2 signaling pathway in the antiangiogenic action of triptolide.

Conclusions

The discovery of an alternative pathway further confirms the value of ethnopharmacological investigations into traditional botanicals for leads for potential drug development.