Traditional preparations of kava (Piper methysticum) inhibit the growth of human colon cancer cells in vitro.

BACKGROUND: Epidemiological studies indicate there is low incidence of colon cancer in the South Pacific islands, including Fiji, West Samoa, and Vanuatu. Cancer incidence has been shown to be inversely associated with kava (Piper methysticum G. Forst.) ingestion. Hypothesis/Purpose: Kava prepared traditionally will inhibit the growth of human cancer cells. This investigation entails preparation and analysis of kava extracts and study of the growth inhibitory activity of the extracts, alone and combined with hibiscus. STUDY DESIGN: We will prepare kava as in Micronesia - as a water extract, high in particulate content, alone or combined with sea hibiscus (Hibiscus tiliaceus L.) - and examine the components and growth inhibitory activity. METHODS: We obtained ground kava prepared in the traditional way from lateral roots and sea hibiscus mucilage and sap from different sources in Micronesia, and prepared water extracts (unfiltered, as well as filtered, since in traditional use the kava beverage contains a high particulate content) and partitions. We used the MTT assay to determine the growth inhibitory activity of the preparations on colon and breast cancer cells and nonmalignant intestinal epithelial cells. LC-MS analysis was used to examine the components of the kava and sea hibiscus extracts and partitions. RESULTS: Traditional preparations of kava inhibit the growth of breast and colon cancer cells. Among the kava preparations, the order of decreasing activity was Fiji(2), Fiji(1), Hawaii; the unfiltered preparations from Fiji were more active than the filtered. Phytochemical analysis indicated that filtering reduced most kavalactone and chalcone content. For example, for Fiji(2), the ratio of dihydromethysticin in filtered/unfiltered kava was 0.01. Thus, for the extracts from Fiji, growth inhibitory activity correlates with the content of these compounds. Unfiltered and filtered kava from Fiji(1) were more active on malignant than nonmalignant intestinal epithelial cells. Since kava is prepared in Micronesia by squeezing the extract through sea hibiscus bark, we assayed the growth inhibitory activity of combinations of kava and sea hibiscus sap and found that sea hibiscus enhanced the growth inhibitory effect of kava. CONCLUSION: Our results show that traditional kava, alone or combined with sea hibiscus, displays activity against human cancer cells and indicate it will be worthwhile to develop and further analyze these preparations to prevent and treat colon and other cancers. Our findings suggest it is important to examine the activity of plants in the form that people consume them.

Screening of the topical anti-inflammatory activity of the bark of Acacia cornigera Willdenow, Byrsonima crassifolia Kunth, Sweetia panamensis Yakovlev and the leaves of Sphagneticola trilobata Hitchcock.

ETHNOPHARMACOLOGICAL RELEVANCE: An investigation of topical anti-inflammatory activity was undertaken on plants used in Central America traditional medicine. AIM OF STUDY: Four herbal drugs used in the folk medicine of Central America to treat inflammatory skin affections (Acacia cornigera bark, Byrsonima crassifolia bark, Sphagneticola trilobata leaves and Sweetia panamensis bark) were evaluated for their topical anti-inflammatory activity. MATERIALS AND METHODS: Petroleum ether, chloroform and methanol extracts were obtained for herbal medicines and then extracts were tested on Croton oil-induced ear dermatitis model in mice. RESULTS: Almost all the extracts reduced the Croton oil-induced ear dermatitis in mice and the chloroform ones showed the highest activity, with ID(50) (dose giving 50% oedema inhibition) values ranging from 112 microg/cm(2) (Byrsonima crassifolia) to 183 microg/cm(2) (Sphagneticola trilobata). As reference, ID(50) of the non-steroidal anti-inflammatory drug indomethacin was 93 microg/cm(2). CONCLUSIONS: Lipophilic extracts from these species can be regarded as potential sources of anti-inflammatory principles.

Analysis of formononetin from black cohosh (Actaea racemosa).

Black cohosh has been widely used as an herbal medicine for the treatment of symptoms related to menopause in America and Europe during the past several decades, but the bioactive constituents are still unknown. Formononetin is an isoflavone with known estrogen-like activity. This compound was first reported to be isolated from black cohosh in 1985, but subsequent research in 2002 using HPLC-PDA and LC-MS revealed no evidence to show the presence of formononetin in 13 populations of American black cohosh. A more recent report published in 2004 claimed to detect formononetin in an extract of black cohosh rhizomes using a TLC-fluorescent densitometry method. To further resolve these conflicting reports, we analyzed black cohosh roots and rhizomes for the presence of formononetin, using a combined TLC, HPLC-PDA and LC-MS method. We examined both methanolic and aqueous methanolic black cohosh extracts by HPLC-PDA and LC-MS methods, and did not detect formononetin in any extracts. We further determined the limits of detection of formononetin by HPLC-PDA and LC-MS. Our experimental results indicated that the sensitivity and accuracy of the HPLC-PDA and LC-MS methods for the analysis of formononetin were slightly higher than those of the reported fluorescent method, suggesting that the HPLC-PDA and LC-MS methods were reliable for the analysis of formononetin from black cohosh. We also repeated the reported TLC method to concentrate two fractions from a modern black cohosh sample and an 86-year-old black cohosh sample, respectively, and then analyzed these two fractions for formononetin using the HPLC-PDA and LC-MS method instead of the fluorescent method. Formononetin was not detected by HPLC-PDA or LC-MS. From the results of the present study it is not reasonable to attribute the estrogen-like activity of black cohosh extracts to formononetin.

The value of plant collections in ethnopharmacology: a case study of an 85-year-old black cohosh (Actaea racemosa L.) sample.

Ethnopharmacological collections of plants used in traditional medical systems are a valuable but often underappreciated resource for scientific investigation. These collections contain many samples of plants currently employed in herbal and pharmaceutical medicine, and questions on stability and storage life can be examined using these historic collections as vouchers. A sample of black cohosh (Actaea racemosa L.), collected in 1919 by the physician and plant explorer Henry Hurd Rusby, was recently identified in the collections of The New York Botanical Garden and analyzed for its triterpene glycosidic and phenolic constituents qualitatively and quantitatively by high-performance liquid chromatography-photodiode array detector (HPLC-PDA) and liquid chromatography-mass spectrophotometry (LC-MS). A comparison of the triterpene glycosidic and phenolic constituents of the 85-year-old plant sample with those of a modern collection of Actaea racemosa showed the similarity of the two samples, confirming the stability of the older sample, despite its curation over the years under a variety of conditions. Quantitative analyses indicated that both plant samples have similar amounts of the four major triterpene glycosides, but the total amount of the six major phenolic constituents measured in the 85-year-old plant material is lower than the amount measured in the modern plant material. Methanol extracts of the two plant materials were tested for their antioxidant activity, and both extracts showed similar antioxidant activity.

Screening of anti-bacterial activity of medicinal plants from Belize (Central America).

Twenty-one extracts from seven herbal drugs, Aristolochia trilobata (Aristolochiaceae) leaves and bark, Bursera simaruba (Burseraceae) bark, Guazuma ulmifolia (Sterculiaceae) bark, Hamelia patens (Rubiaceae) leaves and Syngonium podophyllum (Araceae) leaves and bark, used in traditional medicine of Belize (Central America) as deep and superficial wound healers, were evaluated for their anti-bacterial properties. Activity was tested against standard strains of Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923 and Enterococcus faecalis ATCC 29212. Almost all the extracts were able to inhibit the growth of one or more of the bacterial strains, except that of Enterococcus faecalis. For the first time an anti-microbial activity is reported for Aristolochia trilobata as well as for Syngonium podophyllum. The hexane extracts of Aristolochia trilobata leaves and bark were the most active extracts against Staphylococcus aureus (MIC=0.31 and 0.625mg/ml, respectively).

Screening of the topical anti-inflammatory activity of some Central American plants.

Hexane, chloroform and methanol extracts of seven herbal drugs used in the folk medicine of Central America against skin disorders (Aristolochia trilobata leaves and bark, Bursera simaruba bark, Hamelia patens leaves, Piper amalago leaves, and Syngonium podophyllum leaves and bark) were evaluated for their topical anti-inflammatory activity against the Croton oil-induced ear oedema in mice. Most of the extracts induced a dose-dependent oedema reduction. The chloroform extract of almost all the drugs exhibited interesting activities with ID(50) values ranging between 108 and 498 micro g/cm(2), comparable to that of indomethacin (93 micro g/cm(2)). Therefore, the tested plants are promising sources of principles with high anti-inflammatory activity.

Therapeutic plants of Ayurveda: a review of selected clinical and other studies for 166 species.

This paper reports on the results of a literature survey involving 166 different species of plants used in the Ayurvedic pharmacopoeia, based on a sampling of the literature available to us. We found a wide range of clinical and other in vivo studies for many of the plant-based therapies utilized in the Ayurvedic system. Of the 166 plants investigated, 72 (43%) had at least one or more human studies and 103 (62%) had one or more animal studies. These results appear to contradict the generally held notion that herbal remedies used in non-Western systems of botanical medicine have not been evaluated in human or in vivo trials. Some of these studies are not always as large or methodologically rigorous as clinical studies reported in major medical journals. Indeed, a critical assessment of the research according to the standards of evidence-based medicine would eliminate many of these studies for lack of rigor according to criteria of randomization, sample size, adequacy of controls, etc. However, the studies do suggest which species might be appropriate for larger and better-controlled trials in the future. Accordingly, a synopsis of the plants, their therapeutic applications, and their clinical or experimental evaluations is presented.

Ethnobotany in the search for vasoactive herbal medicines.

Plant samples derived from ethno-directed and random collections were screened to determine their effect on pre-contracted rat aortic tissue. Of the 31 ethno-directed species, four were found to be potent relaxants of vascular smooth muscle. The vasoactive species were Chamguava gentlei, Alseis yucatanensis, Licaria peckii and Nectandra salicifolia. None of the 32 randomly collected samples produced a relaxation response. These data support the hypothesis that ethno-directed collection is a more efficient means of drug discovery than random plant screens.

Two new lignans with activity against influenza virus from the medicinal plant Rhinacanthus nasutus.

Two new lignans, rhinacanthin E (1) and rhinacanthin F (2), were isolated from the aerial parts of the plant Rhinacanthus nasutus. Their structures were established by detailed spectroscopic analysis. These compounds show significant antiviral activity against influenza virus type A.

8-O-acetylharpagide is a nonsteroidal ecdysteroid agonist.

We have identified a novel nonsteroidal ecdysteroid agonist. This compound was isolated from a methanol extract of Ajuga reptans L. (Lamiaceae) and the structure was identified by spectroscopic methods as 8-O-acetylharpagide. We have characterised this compound as an ecdysteroid agonist in a transactivation assay using beta-galactosidase as the reporter gene regulated by ecdysteroid response elements. In this assay, 8-O-acetylharpagide has an EC50 of 22 microM. The compound also competes with tritiated-ponasterone A for binding to the Drosophila ecdysteroid receptor. Finally, it induces differentiation of Drosophila Kc cells as would be expected of an ecdysteroid agonist. This iridoid glycoside is common to several plant species and may play a role in the natural defense mechanisms of plants.

Inactivation of cell surface receptors by pheophorbide a, a green pigment isolated from Psychotria acuminata.

The inhibition of cytokine and monoclonal antibody binding cell surfaces caused by an extract of Psychotria acuminata, a medicinal plant used in the traditional medicine of the people of Belize (Central Africa), was attributed to the presence of pheophorbide a and pyropheophorbide a. Since the binding of tumor necrosis factor-alpha, interleukin-8, complement factor 5a as well as epidermal growth factor to target cells was dramatically reduced, the inhibition was not receptor or cytokine specific. In addition, the respective binding of radiolabeled monoclonal antibodies CL203 and R15.7 to the cell surface antigens intracellular cell adhesion molecule-1 and lymphocyte function-associated antigen-1 beta-chain was decreased by pretreatment of cells with pheophorbide a as well. In all cases, the inhibition by pheophorbides was dependent on the simultaneous presence of light, indicating causative involvement of a photodynamic process. These observations are not unique to pheophorbides and can be extended to porphyrins as well as to other photodynamic agents. Cytotoxicity resulting from photodynamic therapy (PDT) has been documented by many studies. Our investigations suggest that the inactivation of cell surface receptors contributes not only to an antitumor effect of PDT but also to the systemic immunosuppression, a serious side effect of PDT.

Novel nematocidal agents from Curcuma comosa.

Curcuma comosa is a member of the economically important plant family, Zingiberaceae. A methanolic extract of C. comosa was shown to be nematocidal when tested against the free-living nematode Caenorhabditis elegans. Five diphenylheptanoids [1-5], one new and four known, have been isolated and shown to be responsible for the activity. This is the first report of three of these compounds [1, 2, 4] being isolated from a natural source.

Ethnobotany, drug development and biodiversity conservation--exploring the linkages.

Numerous ethnobotanical studies aimed at identifying new pharmaceutical products have been initiated in recent times. Ethnobotany has once again become a recognized tool in the search for new pharmaceuticals. Initiatives by governmental agencies and the private sector have helped spark this renewal. Many of these projects are interdisciplinary efforts involving scientists from the fields of anthropology, botany, medicine, pharmacology and chemistry. The Belize Ethnobotany Project links pharmaceutical prospecting with the conservation of traditional medical systems and biological resources. It illustrates the concept of the 'ethno-biomedical reserve' and provides an opportunity for pharmaceutical and herbal industries to contribute to the conservation effort. Terra Nova Rainforest Reserve is an ethno-biomedical reserve in Belize that was given legal status in June of 1993. Too often the exploitation of wild harvested resources has led to their severe degradation. There is a need for increased efforts to develop technologies to sustain their extraction.

Ethnobotany and the identification of therapeutic agents from the rainforest.

Many rainforest plant species, including trees and herbaceous plants, are employed as medicines by indigenous people. In much of the American tropics, locally harvested herbal medicines are used for a significant portion of the primary health care, in both rural and urban areas. An experienced curandero or herbal healer is familiar with those species with marked biological activity, which are often classified as 'powerful plants'. Examples are given from studies in progress since 1987 in Belize, Central America. The Institute of Economic Botany of The New York Botanical Garden is collaborating with the National Cancer Institute in Bethesda, Maryland (USA) in the search for higher plants with anti-AIDS and anticancer activity. Several strategies are cited for identification of promising leads from among the circa 110,000 species of higher plants that are present in the neotropics, the focus of this search. Recommendations are offered for the design of future efforts to identify plant leads for pharmaceutical testing.

Oligarchic forests of economic plants in amazonia: utilization and conservation of an important tropical resource.

Tropical forests dominated by only one or two tree species occupy tens of millions of hectares in Ammonia In many cases, the dominant species produce fruits, seeds, or oils of economic importance. Oligarchic (Gr. oligo = few, archic = dominated or ruled by) forests of six economic species, i. e., Euterpe oleracea, Grias peruviana, Jessenia bataua, Mauritia flexuosa, Myrciaria dubia, and Orbignya phalerata, were studied in Brazil and Peru Natural populations of these species contain from 100 to 3,000 conspecific adult trees/ha and produce up to 11.1 metric tons of fruit/hd/yr. These plant populations are utilized and occasionally managed, by rural inhabitants in the region. Periodic fruit harvests, if properly controlled have only a minimal impact on forest structure and function, yet can generate substantial economic returns Market-oriented extraction of the fruits produced by oligarchic forests appears to represent a promising alternative for reconciling the development and conservation of Amazonian forests.