Bioactive small-molecule constituents of Lao plants.

Laos has a rich plant diversity, and medicinal plants are used extensively in Lao traditional medicine for the treatment of a variety of human diseases. However, only a relatively small number of these plants have been investigated for their major components with potential antitumor, anti-infective, and other types of bioactivities. These species include Asparagus cochinchinensis, Diospyros quaesita, Gongronema napalense, Marsypopetalum modestum, Nauclea orientalis, Rourea minor, Stemona pierrei, and Stemona tuberosa. Thus far, the bioactive compounds isolated from these Lao plants include alkaloids, glycerol esters, phenolic compounds such as lignans and stilbenoids, steroids, and triterpenoids. Of these, the norlignan, nyasol (1b), the triterpenes, pyracrenic acid [3ß-O-trans-caffeoylbetulinic acid (3)] and betulinic acid (3b), and the dimeric thiopyridine, dipyrithione (5), were found to show both cancer cell cytotoxicity and anti-infective activity. The present review focuses on examples of promising lead compounds isolated from Lao plants, with their possible development as potential therapeutic agents being discussed. It is hoped that this contribution will provide useful information on higher plants growing in Laos to help stimulate future discoveries of potential agents for the treatment of cancer, infections, and other diseases.

Cytotoxicity and Preliminary Analysis of the Pro-apoptotic and Cell Cycle Arrest Effects of Lantana ukambensis Against Colorectal Cancer Cells.

Lantana ukambensis (Vatke) Verdc. (Verbenaceae) is a seasonal herb widely spread in the West African region. The whole plant is used for the treatment of wounds, infections, and inflammatory pathologies. The purpose of this research is to evaluate the cytotoxicity and to analyze the probable pro-apototic, and cell cycle arrest effects of L. ukambensis methylene chloride extract and its fractions against HCT-116 and HT-29 colorectal cancer cells using preliminary tests in order to highlight the interest of this plant in the search of new anticancer molecules. The dried powder of the whole plant was extracted by methylene chloride maceration for 24 hours and the extract was divided into five fractions. The cytotoxicity of the crude extract and fractions were evaluated by the MTS assay. The most active fractions were subjected to some preliminary assays including crystal violet, Hoechst staining, cell cycle arrest, and annexin V/PI assays on the cancer cells to highlight the probable mechanism of action of these fractions. The methylene chloride, ethyl acetate, and 1-butanol fractions of L. ukambensis crude extract demonstrated significant antiproliferative effects on HCT-116 and HT-29 cell growth with IC50 values ranging between 2 to 15 µg/mL. 1-butanol and ethyl acetate fractions decreased the G1 phase by 20.53% and 28.47% and increased the G2/M by 23.47% and 25.90% respectively on HCT-116. Moreover, 1-butanol fraction increased the cumulative value of apoptotic cells by 49.77% on HCT-116 and ethyl acetate fraction increased this value by 53.37% at 15 µg/mL after 48 hours of exposure. The outcome of this study suggests the potential of 1-butanol and ethyl acetate fractions for the isolation of anticancer molecules against colorectal cancer.

Revisiting the linkage between ethnomedical use and development of new medicines: A novel plant collection strategy towards the discovery of anticancer agents.

The Vietnam-Laos International Cooperative Biodiversity Group (ICBG) based at the University of Illinois at Chicago (UIC) catalyzed a country-wide network of medicinal plant preserves (MPP) and medicinal biodiversity preserves (MBP) now established in ten provinces of the Lao People's Democratic Republic (Lao PDR), which are relied upon as protected sources of ethnomedicines for local villagers and traditional healers. In collaboration with the Lao PDR's Institute of Traditional Medicine (ITM), our ongoing P01 Program Project (Ohio State University) examined the anticancer bioprospecting potential for two of the most exhaustively inventoried of these sites: the Bolikhamxay MPP and the Xiengkhouang MBP. Guided by prior voucher specimens sourced from these preserves with an overwhelming emphasis on plants employed in traditional medicine, 201 distinct samples from 96 species were collected along with proper herbarium documentation. Aliquots of these plant samples were extracted in azeotropic ethanol and evaporated to dryness for initial biological evaluation. In six samples from six different species (2.99% of the collected samples, 6.25% of taxa) it was observed that extracts exhibited notable cytotoxicity against HT-29 colon adenocarcinoma cells. The wisdom behind the utilization of HT-29 cells in this preliminary biological screen is discussed. Furthermore, comparison of screening results based on longstanding considerations and ideological underpinnings of ethnobotanical vs. "random" biodiversity-based collection approaches is detailed herein. The results of this interdisciplinary study support the hypothesis that, by privileging the initial sample set in terms of human safety and pharmacological activity, ethnobotanically driven collection for biological screening efforts can produce leads unprecedented by the strict traditional usages of plants.

Indigenous knowledge of medicinal plants among Dozo hunters: an ethnobotanical survey in Niamberla village, Burkina Faso.

OBJECTIVES: This investigation aims to provide a database of Dozo traditional knowledge of medicinal plants used for the treatment of common diseases. DESIGN: The study was conducted through individual interviews using a survey form. Data were recorded in a database allowing statistical analysis. Each plant was recorded and documented with a herbarium specimen. Settings/Location & Subjects: The term Dozo refers to great hunters from Burkina Faso, highly renowned for their knowledge of medicinal plants. Niamberla village was founded by Dozo hunters and is currently the residence of many traditional healers. Unfortunately, their indigenous knowledge is not well recorded and may be lost between two generations. RESULTS: A total of 16 traditional healers were interviewed, giving 89 recipes for the treatment of 37 diseases. The most common diseases are malaria (13%), psychological/spiritual issues (12%), gastric disorders (11%), sexually transmitted diseases (10%), and wounds (8%). A total of 56 medicinal plants have been identified, consisting mostly of trees (44%), shrubs (34%), and herbs (16%). CONCLUSIONS: The results of this research provide a basis for pharmacological and toxicological investigations and are necessary to preserve the indigenous knowledge of traditional medicine among Dozo hunters.

Assessment of the importance of medicinal plants among communities around Khiat Ngong of southern Laos.

A field survey was launched to identify medicinal plants growing in the Khiat Ngong wetlands and surrounding forested areas of Pathoumphone District, Champasak Province in southern Laos. In this area, 418 plants representing approximately 250 species, belonging to at least 200 genera in 93 families of vascular plants, are used by traditional healers to treat more than 95 symptoms. A large number of species are used for treating fever. At least 14 plant species have not been previously reported for having medicinal properties. At least 10 have previously been investigated and have shown interesting biological activity by other researchers, signaling promising candidates for income-generating activities.

New finding of an anti-TB compound in the genus Marsypopetalum (Annonaceae) from a traditional herbal remedy of Laos.

ETHNOPHARMACOLOGICAL RELEVANCE: There is widespread use of traditional herbal remedies in the Lao PDR (Laos). It is common practice to treat many diseases with local plants. This research project documented and analysed some of these traditional remedies used to treat symptoms of tuberculosis (TB). MATERIALS AND METHODS: This research was executed by interviewing healers about plants used traditionally to treat the symptoms of TB. Samples of some of the plants were collected, and extracts of 77 species were submitted to various in vitro assays in order to determine the amount of growth inhibition of virulent Mycobacterium tuberculosis H37Rv (Mtb), as opposed to other microbes and mammalian Vero cells. RESULTS: Interviews took place with 58 contemporary healers in 5 different provinces about plants currently used, giving a list of 341 plants. Bioassay-guided fractionation was performed on Marsypopetalum modestum (Pierre) B. Xue and R.M.K. Saunders (Annonaceae), leading to the isolation of dipyrithione, an anti-mycobacterial compound isolated for the first time from the genus Marsypopetalum through this research. CONCLUSIONS: This research has helped to increase awareness of Laos' rich diversity of medicinal plants and will hopefully provide incentive to preserve the undeveloped forested areas that remain, which still hold a wealth of medical information for future discoveries.

Folk Epidemiology Recorded in Palm Leaf Manuscripts of Laos.

In an effort to preserve traditional medicine knowledge and to uncover information about disease patterns and treatment in the Lao People's Democratic Republic (PDR), linguistic experts have scanned centuries-old medical palm leaf manuscripts for disease entries. A list of more than 7000 diseases has resulted, shedding valuable light onto the medical history and traditional medicine heritage of the people of Laos, as well as providing an index for faster research into specific diseases and their traditional treatments.

Biological evaluation of plants of Laos used in the treatment of tuberculosis in Lao traditional medicine.

Tuberculosis has existed in Southeast Asia for thousands of years. Many traditional treatments involve herbal remedies. Over time, these traditional treatments have had the chance to become refined based on efficacy and safety. It was therefore hypothesized that plants that were used in the past and are still used today to treat symptoms associated with tuberculosis are more likely to contain anti-tubercular compounds than plants that have not been used continuously. To try to deduce which plants were used in Laos in the past, a collection of palm leaf manuscripts was studied and a list of plants used to treat symptoms associated with tuberculosis was compiled. Interviews were then conducted with contemporary healers to see if the same plants are still being used today. Plants that were found in the manuscripts and/or are presently used by healers were collected, extracted and were evaluated in an anti-tubercular assay. This paper presents the methods used to identify and collect plants used to treat symptoms indicative of tuberculosis, and the results of anti-TB assays to test for activity.