DNA-damaging steroidal alkaloids from Eclipta alba from the suriname rainforest1

Unlocking Therapeutic Potential: Comprehensive Extraction, Profiling, and Pharmacological Evaluation of Bioactive Compounds from Eclipta alba (L.) Hassk. for Dermatological Applications

Herbal medicine has been studied as an alternate approach to modern medicine as it is more cost-effective and accessible via natural sources. Eclipta alba (E. alba, L.) Hassk. is a weed plant abundantly distributed throughout different regions of the world and contains abundant bioactive compounds used for various skin conditions. In this review, we aimed to gather information from the literature about the extraction, separation, and identification of these bioactive compounds and their potential in skin diseases. Relevant studies published before August 2023 were identified and selected from electronic databases, including Scopus, SciFinder, ScienceDirect, Google Scholar, and Wiley Library, using the following keywords: Eclipta alba, Eclipta prostrata, phytochemicals, extraction, separation, isolation, identification, characterization, pharmacological activity, and skin conditions. Up-to-date extraction, separation, and identification methods of bioactive compounds from E. alba and their skin-related pharmacological activities are discussed in this review. As there are limitations regarding extraction, separation, and identification methods, and in-depth mechanistic and human studies of the skin-related pharmacological activities of bioactive compounds, these gaps are areas for future research to expand our understanding and broaden the potential applications of this medicinal weed plant, including the development of cosmeceutical and skincare products, anti-inflammatory agents, and formulations for dermatological treatments.

Steroidal alkaloids from the roots of Veratrum stenophyllum

Three new steroidal alkaloids, veratrasines A - C (1-3), along with ten known analogues (4-13) were isolated from the roots of Veratrum stenophyllum. Their structures were elucidated by NMR and HRESIMS data and comparison with the reported data in the literatures. A plausible biosynthetic pathway for 1 and 2 were proposed. Compounds 1, 3, and 8 showed moderate cytotoxic activity against MHCC97H and H1299 cell lines.

In silico toxicity prediction, molecular docking studies and in vitro validation of antibacterial potential of alkaloids from Eclipta alba in designing of novel antimicrobial therapeutic strategies

The rapid emergence of various drug resistance and unfavourable aliphatic medication side effects endangers people's health. Phytocompounds with antibacterial activity and less harmful effects are known to be present in medicinal plants. Alkaloids from Eclipta alba were tested for their in vitro antibacterial capabilities and in silico docking studies against pathogenic bacteria and their target proteins in the current investigation. The alkaloid compounds verazine, ecliptine, 4-hydroxyverazine, 20-Epi-4beta-hydroxyverazine and hydroxyverazine were subjected to molecular docking studies to determine the method of binding as well as potential interactions and the docking score. The in vitro antibacterial activity of verazine alkaloid was assessed against two gram-positive and two gram-negative bacteria. Verazine alkaloid has the best inhibitory ability against DNA gyrase of E. coli (ΔG= -8.44 kcal/mol) and dihydrofolate reductase (DHFR) of S. aureus (ΔG= -10.04 kcal/mol), according to docking studies. Verazine shown substantial in vitro antibacterial activity in this investigation against all test bacteria, with MIC and MBC values of 31.25 and 62.50 µg/mL for S. aureus and 15.63 and 31.25 µg/mL for B. cereus, respectively. The results of this work highlighted the value of unique alkaloid compounds from E. alba, which may offer effective antibacterial agents and DNA gyrase, DHFR inhibitors due to their novel structural properties capable of combating antimicrobial resistance. These findings call for more investigation into the compounds' function as antibacterial agents, as well as their unique-binding locations and mechanisms.

Veratrum parviflorum: An Underexplored Source for Bioactive Steroidal Alkaloids

Plants of the Veratrum genus have been used throughout history for their emetic properties, rheumatism, and for the treatment of high blood pressure. However, inadvertent consumption of these plants, which resemble wild ramps, induces life-threatening side effects attributable to an abundance of steroidal alkaloids. Several of the steroidal alkaloids from Veratrum spp. have been investigated for their ability to antagonize the Hedgehog (Hh) signaling pathway, a key pathway for embryonic development and cell proliferation. Uncontrolled activation of this pathway is linked to the development of various cancers; most notably, basal cell carcinoma and acute myeloid leukemia. Additional investigation of Veratrum spp. may lead to the identification of novel alkaloids with the potential to serve as chemotherapeutics. V. parviflorum is a relatively uncommon species of Veratrum that resides in the southeastern regions of North America. The phytochemical profile of this plant remains largely unexplored; however, bioactive steroidal alkaloids, including cyclopamine, veratramine, veratridine, and verazine were identified in its extract. The structural elucidation and bioactivity assessment of steroidal alkaloids in lesser abundance within the extract of V. parviflorum may yield potent Hh pathway inhibitors. This review seeks to consolidate the botanical and phytochemical information regarding V. parviflorum.

Eclipta prostrata (L.) L. (Asteraceae): Ethnomedicinal Uses, Chemical Constituents, and Biological Activities

Eclipta prostrata (L.) L. (Syn.: Eclipta alba (L.) Hassak, Family: Asteraceae) is an important medicinal plant in the tropical and subtropical regions. It is widely used in treating various diseases of skin, liver and stomach in India, Nepal, Bangladesh, and other countries. The main aim of this review was to collect and analyze the available information on traditional uses, phytoconstituents, and biological activities of E. prostrata. The scientific information was collected from the online bibliographic databases such as Scopus, MEDLINE/PubMed, Google Scholar, SciFinder, etc. and books and proceedings. The active phytochemicals were coumestan derivatives, phenolic acid derivatives, flavonoids, triterpenoid and steroid saponins, substituted thiophenes, etc. Various extracts and isolated compounds of E. prostrata showed a wide range of biological activities such as antimicrobial, anticancer, hepatoprotective, neuroprotective and hair growth promoting activities. Relatively a few studies have been performed to reveal the exact phytoconstituents responsible for their corresponding pharmacological activities. Future studies should focus on detailed mechanism based studies using animal models and clinical studies.

Review: Veratrum californicum Alkaloids

Veratrum spp. grow throughout the world and are especially prevalent in high mountain meadows of North America. All parts of Veratrum plants have been used for the treatment of ailments including injuries, hypertension, and rheumatic pain since as far back as the 1600s. Of the 17-45 Veratrum spp., Veratrum californicum alkaloids have been proven to possess favorable medicinal properties associated with inhibition of hedgehog (Hh) pathway signaling. Aberrant Hh signaling leads to proliferation of over 20 cancers, including basal cell carcinoma, prostate and colon among others. Six of the most well-studied V. californicum alkaloids are cyclopamine (1), veratramine (2), isorubijervine (3), muldamine (4), cycloposine (5), and veratrosine (6). Recent inspection of the ethanolic extract from V. californicum root and rhizome via liquid chromatography-mass spectrometry has detected up to five additional alkaloids that are proposed to be verazine (7), etioline (8), tetrahydrojervine (9), dihydrojervine (10), 22-keto-26-aminocholesterol (11). For each alkaloid identified or proposed in V. californicum, this review surveys literature precedents for extraction methods, isolation, identification, characterization and bioactivity to guide natural product drug discovery associated with this medicinal plant.

Potential of Steroidal Alkaloids in Cancer: Perspective Insight Into Structure-Activity Relationships

Steroidal alkaloids contain both steroidal and alkaloid properties in terms of chemical properties and pharmacological activities. Due to outstanding biological activities such as alkaloids and similar pharmacological effects to other steroids, steroidal alkaloids have received special attention in anticancer activity recently. Substituted groups in chemical structure play markedly important roles in biological activities. Therefore, the effective way to obtain lead compounds quickly is structural modification, which is guided by structure-activity relationships (SARs). This review presents the SAR of steroidal alkaloids and anticancer, including pregnane alkaloids, cyclopregnane alkaloids, cholestane alkaloids, C-nor-D-homosteroidal alkaloids, and bis-steroidal pyrazine. A summary of SAR can powerfully help to design and synthesize more lead compounds.

Steroidal alkaloids isolated from Veratrum grandiflorum Loes. as novel Smoothened inhibitors with anti-proliferation effects on DAOY medulloblastoma cells

Constitutive activation of Hedgehog (Hh) pathway is intimately related with the occurrence and development of several malignancies, such as medulloblastoma (MB) and other tumors. Therefore, small molecular inhibitors of Hh pathway are urgently needed. In this study, three new steroidal alkaloids, ⊿⁵ (20R, 24R) 23-oxo-24-methylsolacongetidine, ⊿⁵ (20S, 24R) 23-oxo-24-methylsolacongetidine and veralinine 3-O-α-l-rhamnopyranosyl-(1 → 2)-β-D-glucopyranoside, together with six known alkaloids, 20-epi-verazine, verazine, protoverine 15-(l)-2'-methylbutyrate, jervine, veramarine and β1-chaconine, were isolated and determined from Veratrum grandiflorum Loes. The dual-luciferase bioassay indicated that all compounds exhibited significant inhibitions of Hh pathway with IC₅₀ values of 0.72-14.31 μM against Shh-LIGHT 2 cells. To determine whether these Hh pathway inhibitors act with the Smoothened (Smo) protein, which is an important oncoprotein and target for this pathway, BODIPY-cyclopamine (BC) competitive binding assay was preferentially performed. Compared with BC alone, all compounds obviously reduced the fluorescence intensities of BC binding with Smo in Smo-overexpression HEK293T cells through fluorescence microscope and flow cytometer. By directly interacting with Smo, it revealed that they were actually novel natural Smo inhibitors. Then, their anti-tumor effects were investigated against the human MB cell line DAOY, which is a typical pediatric brain tumor cells line with highly expressed Hh pathway. Interestingly, most of compounds had slight proliferation inhibitions on DAOY cells after treatment for 24 h same as vismodegib, while β1-chaconine showed the strongest inhibitory effect on the growth of DAOY with IC₅₀ value of 5.35 μM. In conclusion, our studies valuably provide several novel natural Smo inhibitors for potential targeting treatment of Hh-dependent tumors.

My 60-Year Love Affair with Natural Products

The author describes his 60-year career in studying the chemistry of natural products, which includes structural, synthetic, and biosynthetic studies of natural products ranging from insect pigments, antibiotics, and fecal mutagens to taxol and other anticancer natural products as well as antimalarial natural products. One of the compounds discussed, napabucasin, is now an anticancer drug in phase III clinical trials.

Two new steroidal alkaloids from the rhizomes of Veratrum nigrum L. and their anti-TYLCV activity

Two new steroidal alkaloids (1-2), together with seven known related steroidal alkaloids (3-9), were isolated from the rhizomes of Veratrum nigrum L. Their structures were elucidated by extensive spectroscopic analysis, and by comparison with literature data. Compound 1 possessed a rare 1, 3-oxazolidine unit within varazine-type alkaloids, and 2 was a 9-hydroxy-4-one derivative of 3-veratroylgermine. All isolates were evaluated inhibit tomato yellow leaf curl virus (TYLCV) activity. Compounds 5 and 7 (40 μg/mL) showed a significant anti-TYLCV activity in the host Nicotiana benthamiana with inhibition rates 74.6% and 63.4%, respectively, which are higher than that of the positive control ningnanmycin (51.4%).

Stereoselective Synthesis of (-)-Verazine and Congeners via a Cascade Ring-Switching Process of Furostan-26-acid

An efficient synthetic strategy for three natural seco-type cholestane alkaloids isolated from the Veratrum plants, based on commercially available naturally occurring and abundant (-)-diosgenin (1), as exemplified in the concise asymmetric synthesis of (-)-verazine (4), (-)-veramiline (5) (proposed structure), and its 22-epimer, (-)-oblonginine (6), is presented. This work highlights the application of a cascade ring-switching process of (-)-diosgenin to achieve the E-ring opening and construction of chiral six-membered lactone challenges in seco-type cholestane alkaloid synthesis. This approach enables the synthesis of related natural and nature-like novel cholestane alkaloids, opening up opportunities for more extensive exploration of cholestane alkaloid biology.

A review on traditional uses, phytochemistry and pharmacology of Eclipta prostrata (L.) L

ETHNOPHARMACOLOGICAL RELEVANCE

Eclipta prostrata, a traditional herbal medicine, has long been used in Asia and South America for the therapy of hemorrhagic diseases (e.g. hemoptysis, hematemesis, hematuria, epistaxis and uterine bleeding), skin diseases, respiratory disorders, coronary heart disease, hair loss, vitiligo, snake bite and those caused by the deficiency of liver and kidney.

AIM OF THE REVIEW

In this review, we highlight relatively comprehensive and up-to-date information of E. prostrata on traditional uses, phytochemistry, pharmacology and toxicity, along with featuring the gaps in current knowledge, aiming to provide references for future research and possible opportunities for well applications of this medicinal plant.

MATERIALS AND METHODS

Information on E. prostrata was gathered from scientific databases (Google Scholar, Web of Science, Scifinder, Baidu Scholar, PubMed and CNKI). Information was also obtained from local books, Ph.D. theses and M.Sc. dissertations and Chinese Pharmacopoeia. The plant taxonomy was validated by the database "The Plant List".

RESULTS

Various phytochemical classes has been identified and isolated from the plant covering triterpenes, flavonoids, thiopenes, coumestans, steroids and others. Among these, coumestans are reported as the most common ingredients. The isolated crude extracts and individual compounds have been reported to exhibit promising pharmacological properties, such as hepatoprotective, osteoprotective, cytotoxic, hypoglycaemic, anti-inflammatory, anti-microbial, hypolipidemic, promoting hair growth, rejuvenative and neuroprotective effects.

CONCLUSIONS

Until now, significant progress has been witnessed in phytochemistry and pharmacology of E. prostrata. Thus, some traditional uses has been well supported and clarified by modern pharmacological studies. Moreover, E. prostrata also showed therapeutic potential in some refractory diseases such as cancer, dementia and diabetes. But, present findings are still insufficient that cannot satisfactorily explain some mechanisms of action. More well-designed studies in vitro especially in vivo are required to establish links between the traditional uses and bioactivities, discover new skeletons and activity molecules, as well as ensure safety before clinical use.

Phytochemistry and neuroprotective effects of Eclipta alba (L.) Hassk

Eclipta alba (L.) Hassk. or Eclipta prostrata (Linn.) or Eclipta erecta (Linn.) is an herbaceous plant well known in Asian as African traditional medicines. These extracts are used in traditional medicine for treatment of microbial diseases and certain metabolic disorders. This review aimed to investigate phytochemical profile and neuroprotective effects of E. alba (L.) Hassk. Several compounds belonging to the families of phenolics, alkaloids, terpenoids and polysaccharides have been isolated, identified or characterized from E. alba extracts. This plant has a diverse neuropharmacological profile. Thus, its extract improves cognitive deficits and also attenuated epileptic seizures. Phytomolecules implicated in these potentials are Eclalbasaponin II and luteolin, respectively. This document updates isolated and identified organic compounds from the extracts of E. alba and reviews their neuropharmacological activities.

Synthesis and Antimicrobial Evaluation of Fire Ant Venom Alkaloid Based 2-Methyl-6-alkyl-Δ1,6-piperideines

The first synthesis of 2-methyl-6-pentadecyl-Δ^1,6-piperideine (1), a major alkaloid of the piperideine chemotype in fire ant venoms, and its analogues, 2-methyl-6-tetradecyl-Δ^1,6-piperideine (2) and 2-methyl-6-hexadecyl-Δ^1,6-piperideine (3), was achieved by a facile synthetic method starting with glutaric acid (4) and urea (5). Compound 1 showed in vitro antifungal activity against Cryptococcus neoformans and Candida albicans with IC₅₀ values of 6.6 and 12.4 μg/mL, respectively, and antibacterial activity against vancomycin-resistant Enterococcus faecium with an IC₅₀ value of 19.4 μg/mL, while compounds 2 and 3 were less active against these pathogens. All three compounds strongly inhibited the parasites Leishmania donovani promastigotes and Trypanosoma brucei with IC₅₀ values in the range of 5.0-6.7 and 2.7-4.0 μg/mL, respectively.

Ethnopharmacological uses, phytochemistry, biological activities, and biotechnological applications of Eclipta prostrata

Eclipta prostrata belongs to a family of medicinal plants (Asteraceae) and plays a role in the treatment of several diseases, including infectious hepatitis, snake venom poisoning, gastritis, and respiratory diseases such as a cough and asthma. A number of compounds, including thiophene derivatives, steroids, triterpenes, flavonoids, polyacetylenes, polypeptides, and coumestans, have been isolated from E. prostrata. The plant functional compounds can act as reducing agent in the field of nanoparticle synthesis. The extracts of E. prostrata are widely used for green biosynthesis of various metal and metal oxide nanoparticles, nanoparticles, which showed a potential for pharmaceutical, biotechnological, and biomedical applications. Establishment of a efficient in vitro regeneration and genetic transformation method of E. prostrata is a vital prerequisite for application of biotechnology in order to improve secondary metabolite yields. The present mini-review discusses its pharmacological profile, chemical constituents, biotechnological, and ethnomedical uses, mainly focusing on antimyotoxic, antihemorrhagic, antiproliferative, antioxidant, antitumor, antihyperglycemic, antidementia, antimicrobial, antihyperlipidemic, antivenom, anti-HIV, and larvicidal activities, so that the pharmaceutical potential of the plant can be better evaluated. The mini review, providing up-to-date phytochemical and other information on E. prostrata, will serve a reference for further studies.

Thiophenes, polyacetylenes and terpenes from the aerial parts of Eclipata prostrate

One new bithiophenes, 5-(but-3-yne-1,2-diol)-50-hydroxy-methyl-2,20-bithiophene (2), two new polyacetylenic glucosides, 3-O-b-D-glucopyranosyloxy-1-hydroxy-4E,6E-tetradecene-8,10,12-triyne (8), (5E)-trideca-1,5-dien-7,9,11-triyne-3,4-diol-4-O-b-D-glucopyranoside (9), six new terpenoid glycosides, rel-(1S,2S,3S,4R,6R)-1,6-epoxy-menthane-2,3-diol-3-O-b-D-glucopyranoside (10), rel-(1S,2S,3S,4R,6R)-3-O-(6-O-caffeoyl-b-D-glucopyranosyl)-1,6-epoxy menthane-2,3-diol (11), (2E,6E)-2,6,10-trimethyl-2,6,11-dodecatriene-1,10-diol-1-O-b-D-glucopyranoside (12), 3b,16b,29-trihydroxy oleanane-12-ene-3-O-b-D-glucopyranoside (13), 3,28-di-O-b-D-glucopyranosyl-3b,16b-dihydroxy oleanane-12-ene-28-oleanlic acid (14), 3-O-b-D-glucopyranosyl-(1?2)-b-D-glucopyranosyl oleanlic-18-ene acid-28-O-b-D-glucopyranoside (15), along with fifteen known compounds (1, 3–7, and 16–24), were isolated from the aerial parts of Eclipta prostrata. Their structures were established by analysis of the spectroscopic data. The isolated compounds 1–9 were tested for activities against dipeptidyl peptidase IV (DPP-IV), compound 7 showed significant antihyperglycemic activities by inhibitory effects on DPP-IV in human plasma in vitro, with IC50 value of 0.51 lM. Compounds 10–24 were tested in vitro against NF-jB-luc 293 cell line induced by LPS. Compounds 12, 15, 16, 19, 21, and 23 exhibited moderate anti-inflammatory activities.

Cytotoxic steroids from the leaves of Dysoxylum binectariferum

Four new cholestane-type (1-4) and two new ergostane-type (5, 6) steroids were isolated from the leaves of Dysoxylum binectariferum. Their structures were elucidated on the basis of spectroscopic analysis, including 1D and 2D NMR techniques. The absolute configurations were established by comparison with the literature and Mo2(OAc)4-induced electronic circular dichroism (ECD) data. All the isolates were evaluated for cytotoxicity against A549 (lung carcinoma), MCF-7 (breast adenocarcinoma), and HepG2 (hepatocellular carcinoma) human cancer cell lines. Three of the new cholestane-type steroids displayed potent antiproliferative effects on the tumor cells with IC50 values ranging from 1.5 to 9.6μM, whereas the two new ergostane-type (5, 6) steroids were deemed inactive.

Development and characterization of phyto-vesicles of wedelolactone for hepatoprotective activity

Wedelolactone is isolated from the dried leaves of Eclipta alba (L.) and reported to be effective as a potential hepatoprotective, antibacterial and anti hemorrhagic. Pharmacokinetic studies of wedelolactone reveal its poor absorption through the intestine. The objective of the present study is to enhance bioavailability of wedelolactone by its complexation with phosphatidyl choline and then formulating it as phyto-vesicles for hepatoprotective activity. The complex of wedelolactone rich fraction was prepared with phosphatidyl choline and characterized on the basis of solubility, melting point, thin layer chromatography (TLC), UV, IR and NMR spectroscopy. The complex was further converted into phyto-vesicles and characterized. The hepatoprotective potential of phyto-vesicles was compared with complex, wedelolactone rich fraction and physical mixture of wedelolactone rich fraction and phosphatidyl choline by in vitro method. The results revealed that hepatoprotective activity is better in case of phyto-vesicles as compared to the complex, physical mixture and the wedelolactone itself. Enhanced bioavailability of the wedelolactone complex may be due to the amphiphillic nature of the complex, which greatly enhance the water and lipid solubility of the compound. The present study clearly indicates the superiority of phyto-vesicles over the complex and wedelolactone, in terms of better absorption and improved hepatoprotective activity.

Synthesis and antifungal activity of natural product-based 6-alkyl-2,3,4,5-tetrahydropyridines

Seven 6-alkyl-2,3,4,5-tetrahydropyridines (5a-5g) that mimic the natural piperideines that were recently identified in fire ant venom have been synthesized. Compounds 5c-5g with C-6 alkyl chain lengths from C14 to C18 showed varying degrees of antifungal activities, with 5e (6-hexadecyl-2,3,4,5-tetrahydropyridine) and 5f (6-heptadecyl-2,3,4,5-tetrahydropyridine) being the most active. Compound 5e exhibited minimum fungicidal concentrations of 3.8, 15.0, 7.5, and 7.5 μg/mL against Cryptococcus neoformans, Candida albicans, Candida glabrata, and Candida krusei, respectively. The antifungal activities of these compounds appear to be associated with the C-6 side chain length. This study represents the first effort to evaluate antifungal activities of synthetic analogues of the newly identified fire ant venom alkaloids.

Evaluation of hydro-alcoholic extract of Eclipta alba for its anticancer potential: an in vitro study

ETHNOPHARMACOLOGICAL RELEVANCE

Eclipta alba is traditionally used as hepatoprotective agent. The study was designed to explore its antiproliferative activity on liver and other related cancer.

AIM OF THE STUDY

The present study was designed to assess and establish the role of Eclipta alba as anti-cancer agent using HepG2, C6 glioma and A498 cell lines as model system.

MATERIALS AND METHODS

Antiproliferative and cytotoxic effects of the Eclipta alba hydroalcoholic extract (EAE) was determined using MTT assay. The expression level of NF-kB was analysed by western blotting and RT PCR. Gelatin zymography was done for gelatinase matrix metalloproteinases (MMP-2 and 9) analysis.

RESULTS

EAE inhibited the cell proliferation in dose dependent manner in HepG2, A498 and C6 glioma cell lines with an IC50 of 22±2.9, 25±3.6 and 50±8.7 μg/ml, respectively. The expression of MMP (2 and 9) was down-regulated with EAE treatment. DNA damage was observed following 72h of extract treatment, leading to apoptosis. Additionally, the expression level of NF-kB was evaluated with western blotting and RT-PCR and was found to be down-regulated/inactivated.

CONCLUSIONS

The data establish the existence of anti-proliferative, DNA damaging and anti-metastasis properties in EAE which is yet unexplored and hold high therapeutic impact.

Biodiversity conservation and drug discovery: Can they be combined? The Suriname and Madagascar experiences

The approach to new drugs through natural products has proved to be the single most successful strategy for the discovery of new drugs, but in recent years its use has been deemphasized by many pharmaceutical companies in favor of approaches based on combinatorial chemistry and genomics, among others.Drug discovery from natural sources requires continued access to plant, marine, and microbial biomass, and so the preservation of tropical rainforests is an important part of our drug discovery program. Sadly, many of the tropical forests of the world are under severe environmental pressure, and deforestation is a serious problem in most tropical countries. One way to combat this loss is to demonstrate their value as potential sources of new pharmaceutical or agrochemical products.As part of an effort to integrate biodiversity conservation and drug discovery with economic development, we initiated an International Cooperative biodiversity Group (ICBG) to discover potential pharmaceuticals from the plant biodiversity of Suriname and Madagascar. The Group, established with funding from agencies of the United States government, involved participants from the USA, Suriname, and Madagascar. The basic approach was to search for bioactive plants in the Suriname and Malagasy flora, and to isolate their bioactive constituents by the best available methods, but the work included capacity building as well as research. Progress on this project will be reported, drawing on results obtained from the isolation of bioactive natural products from Suriname and Madagascar. The benefits of this general approach to biodiversity and drug discovery will also be discussed.

Severe hepatotoxicity by Indian Ayurvedic herbal products: a structured causality assessment

The case of a 64 year old female patient is presented who has treated herself for 9 months with various Indian Ayurvedic herbal products for her vitiligo and experienced a causally related severe hepatotoxicity (ALT, 601 U/L; AST, 663 U/L; Bilirubin, 5.0 mg/dL). After discontinuation, a rapid improvement was observed. Causality assessment with the updated CIOMS (Council for International Organizations of Medical Sciences) scale showed a probable causality (+8 points) for Bakuchi tablets containing extracts from Psoralea corylifolia leaves with psoralens as ingredients, as the primary candidate causing the hepatotoxic reaction. The degree of probability was lower with +6 points for other used herbs: Khadin tablets containing extracts from Acacia catechu leaves; Brahmi tablets containing Eclipta alba or Bacopa monnieri; and Usheer tea prepared from Vetivexia zizaniodis. The case is the first report of Indian Ayurvedic herbal products being potentially hepatotoxic in analogy to some other herbs.

Antifungal activities of extracts from Thai medicinal plants against opportunistic fungal pathogens associated with AIDS patients

Summary In this study, 36 extracts derived from 10 plant species were selected to screen for their antifungal activity against clinical isolates of Candida albicans, Cryptococcus neoformans and Microsporum gypseum. Selection was based on their use by traditional Thai healers or their reported antimicrobial activities in an attempt to find bioactive medicines for use in the treatment of opportunistic fungal infections in AIDS patients. The disc diffusion and hyphal extension-inhibition assays were primarily used to test for inhibition of growth. Minimum inhibitory concentration was determined by dilution methods. The chloroform extracts of Alpinia galanga and Boesenbergia pandurata had pronounced antifungal activity against C. neoformans and M. gypseum, but exhibited weak activity against C. albicans. Alpinia galanga and B. pandurata are excellent candidates for the development of a remedy for opportunistic fungal infections in AIDS patients.

Medicinal plants used for dogs in Trinidad and Tobago

This paper documents ethnoveterinary medicines used to treat dogs in Trinidad and Tobago. In 1995, a 4-stage process was used to conduct the research and document the ethnoveterinary practices. Twenty-eight ethnoveterinary respondents were identified using the school-essay method, which is a modified rapid rural appraisal (RRA) technique. Semi-structured interviews were held with these respondents as well as with 30 veterinarians, 27 extension officers and 19 animal-health assistants and/or agricultural officers, and the seven key respondents that they identified. The final step involved hosting four participatory workshops with 55 of the respondents interviewed to discuss the ethnoveterinary data generated from the interviews and to determine dosages for some of the plants mentioned. Supplementary interviews were conducted in 1997 and 1998. Seeds of Carica papaya, and leaves of Cassia alata, Azadirachta indica, Gossypium spp., Cajanus cajan and Chenopodium ambrosiodes are used as anthelmintics. The anthelmintics Gossypium spp. and Chenopodium ambrosiodes are the most frequently used species. Crescentia cujete pulp, Musa spp. stem exudate, the inside of the pods of Bixa orellana, leaves of Cordia curassavica and Eclipta alba plant tops are used for skin diseases. Musa spp. stem exudate, seeds of Manilkara zapota, Pouteria sapota and Mammea americana and leaves of Cordia curassavica, Scoparia dulcis and Nicotiana tabacum are used to control ectoparasites. Dogs are groomed with the leaves of Cordia curassavica, Bambusa vulgaris and Scoparia dulcis. Psidium guajava buds and leaves and the bark of Anacardium occidentale are used for diarrhoea. Owners attempt to achieve milk let-down with a decoction of the leaves of Stachytarpheta jamaicensis. The plant uses parallel those practised in human folk medicine in other Caribbean countries and in other tropical countries.