Medicinal plants from swidden fallows and sacred forest of the Karen and the Lawa in Thailand

Soil fertility in slash and burn agricultural systems in central Mozambique

Slash and burn is a land use practice widespread all over the world, and nowadays it is formally recognized as the principal livelihood system in rural areas of South America, Asia, and Africa. The practice consists of a land rotation where users cut native or secondary forest to establish a new crop field and, in some cases, build charcoal kilns with the cut wood to produce charcoal. Due to several socio-economic changes in developing countries, some scientists and international organizations have questioned the sustainability of slash and burn since in some cases, crop yield does not justify the soil degradation caused. To estimate the soil quality in agricultural and forest soils at different ages of the forest-fallow period (25, 35, and 50 years), this survey investigated rural areas in three locations in Manica province, central Mozambique: Vanduzi, Sussundenga, and Macate. Soil profiles were trenched and sampled with a pedological approach under crop fields and forest-fallow. The chronosequence was selected to test the hypothesis that the increase in forest-fallow age causes an improvement of soil fertility. Results highlighted discrete variations among locations in mineralogy, Al- and Fe-oxyhydroxides, sand, silt, pH, total organic carbon, humic carbon, total nitrogen, available phosphorous, chloride, nitrate, fluoride, and ammonium. Few differences in mineralogy, Fe-oxyhydroxides, available P, chloride, and nitrate were detected between crop fields and forest-fallow within the same location. Such differences were mostly ascribed to intrinsic fertility inherited from the parent material rather than a longer forest-fallow period. However, physicochemical soil property improvement did not occur under a forest age of 50 years (the longest forest-fallow considered), indicating that harmonization of intrinsic fertility and agronomic practices may increase soil organic matter and nutrient contents more than a long forest-fallow period.

Nutrient and Mineral Compositions of Wild Leafy Vegetables of the Karen and Lawa Communities in Thailand

Wild food plants are commonly used in the traditional diets of indigenous people in many parts of the world, including northern Thailand. The potential contribution of wild food plants to the nutrition of the Karen and Lawa communities remains poorly understood. Wild food plants, with a focus on leafy vegetables, were ranked by the Cultural Food Significance Index (CFSI) based on semi-structured interviews. Twelve wild plant species were highly mentioned and widely consumed. The importance of the wild vegetables was mainly related to taste, availability, and multifunctionality of the species. Their contents of proximate and minerals (P, K, Na, Ca, Mg, Fe, Mn, Zn, and Cu) were analyzed using standard methods. The proximate contents were comparable to most domesticated vegetables. The contents of Mg (104 mg/100 g FW), Fe (11 mg/100 g FW), and Zn (19 mg/100 g FW) in the wild leafy vegetables were high enough to cover the daily recommended dietary allowances of adults (19-50 years), whereas a few species showed Mn contents higher than the tolerable upper intake level (>11 mg/100 g edible part). The wild leafy vegetables, therefore, are good sources of minerals and we recommend their continued usage by indigenous people. Further research on these wild leafy vegetables' contents of antioxidants, vitamins, heavy metals, anti-nutrient factors, and food safety is recommended.

Asian elephant self-medication as a source of ethnoveterinary knowledge among Karen mahouts in northern Thailand

ETHNOPHARMACOLOGICAL RELEVANCE

Ethnoveterinary medicine is often assumed to be a subset of human medicinal knowledge. Here we investigate the possibility that some ethnoveterinary medicine rather originates from observations of animal self-medication. We document and analyze the ethnoveterinary medicine used by Karen mahouts for elephant care and attempt to determine whether this knowledge originated from humans or elephants.

MATERIALS AND METHODS

Elephant camp owners and mahouts in four communities in northern Thailand were interviewed about their knowledge and use of plants for ethnoveterinary elephant care. For each ethnoveterinary plant, data were collected on Karen human medicinal uses and whether elephants independently consume them. Based on overlaps between ethnoveterinary use, human medicinal use and elephant dietary use, plants were classified into three categories: those that originated from Karen human medicine, those that originated from Asian elephant self-medication, and those which were present in both human and elephant knowledge traditions.

RESULTS

The use of 34 plants (32 identified at least to genus) and two additional non-plant remedies (salt and human urine) were reported to be used in ethnoveterinary elephant medicine. A total of 44 treatments in 11 use categories were recorded: tonic, wounds, compress, eye problems, indigestion, broken bones, galactagogue, snakebite, fatigue, skin and musth regulation. Of the ethnoveterinary plants, 55% had the same use in human medicine, 43% had different uses and 2% had no use. Elephants consume 84% of the ethnoveterinary plants as part of their natural diet.

DISCUSSION

Analysis indicates that 32% of plant uses likely originated from Karen human medicine, 60% of plant uses likely existed independently in both human and elephant knowledge systems, and 8% of plant uses likely originated from elephant self-medicating behavior. The tonic use category shows the strongest evidence of influence from observations of elephant self-medication. The use of tonic medicines appears to be increasing as a way to mitigate the unnaturally limited diet of elephants in tourist camps.

CONCLUSION

Ethnoveterinary medicine for elephant care is influenced by both human medicinal knowledge and elephant knowledge of plants for self-medication. The ethnoveterinary knowledge domain appears to be the result of an interactive process linked to convergent evolution or co-evolution between humans and Asian elephants.

Medicinal Plants for Treating Musculoskeletal Disorders among Karen in Thailand

Millions of people suffer from Musculoskeletal System Disorders (MSDs), including Karen people who work hard in the fields for their subsistence and have done so for generations. This has forced the Karen to use many medicinal plants to treat MSDs. We gathered data from 15 original references covering 27 Karen communities and we document 461 reports of the use of 175 species for treating MSDs among the Karen people in Thailand. The data were analyzed by calculating use values (UV), relative frequency of citation (RFC) and informant consensus factor (ICF). Many use reports and species were from Leguminosae and Zingiberaceae. Roots and leaves were the most used parts, while the preferred preparation methods were decoction and burning. Oral ingestion was the most common form of administration. The most common ailment was muscle pain. Sambucus javanica and Plantago major were the most important species because they had the highest and second-highest values for both UV and RFC, respectively. This study revealed that the Karen people in Thailand use various medicinal plants to treat MSDs. These are the main resources for the further development of inexpensive treatments of MSDs that would benefit not only the Karen, but all people who suffer from MSD.

New Flavanol Dimers from the Bark of Celtis tetrandra and Their TRAIL Resistance-Overcoming Activity

In the courses of our search for bioactive natural products on TRAIL resistance-overcoming activity, the active EtOAc extract from the bark of Celtis tetrandra was chemically investigated. The fractionation of the extract resulted in the isolation of flavanols; (+)-afzelechin (1), (-)- epiafzelechin (2), (-)-catechin (3), and two new flavanol dimers; (-)- epiafzelechin-(4α→8)-(-)-catechin (4) and (-)- epiafzelechin-(4α→8)-(-)- epicatechin (5). All isolated compounds 1-5 were tested for their TRAIL resistance-overcoming activity against AGS cells at the concentrations from 5–20 μM. It is likely that the flavanol dimers 4 and 5 exhibited weak activity in the range of the concentration of 10–20 μM as compared with the standard.

Antibacterial activity of Litsea cubeba (Lauraceae, May Chang) and its effects on the biological response of common carp Cyprinus carpio challenged with Aeromonas hydrophila

AIMS

The aims of this study were to characterize the antibacterial activity and the chemotype of Litsea cubeba leaf essential oil (EO) harvested in North Vietnam and to investigate the biological effects induced by the leaf powder on growth, nonspecific immunity and survival of common carp (Cyprinus carpio) challenged with Aeromonas hydrophila.

METHODS AND RESULTS

The EO showed the prevalence of linalool (95%, n = 5). It was bactericidal against the majority of tested strains, with minimum inhibitory concentrations ranging from 0·72 to 2·89 mg ml(-1) (Aer. hydrophila, Edwarsiella tarda, Vibrio furnissii, Vibrio parahaemolyticus, Streptococcus garvieae, Escherichia coli, Salmonella Typhimurium). The fish was fed with 0 (control), 2, 4 and 8% leaf powder supplementation diets for 21 days. Nonspecific immunity parameters (lysozyme, haemolytic and bactericidal activities of plasma) were assessed 21 days after feeding period and before the experimental infection. Weight gain, specific growth rate and feed conversion ratio were improved by supplementation of L. cubeba in a dose-related manner, and a significant difference appeared at the highest dose (8%) when compared to the control. The increase in plasma lysozyme was significant for all the treated groups. Haemolysis activity was higher for the groups fed with 4 and 8% plant powder. Antibacterial activity increased significantly for the 8% dose only.

CONCLUSIONS

Litsea cubeba leaf powder increased nonspecific immunity of carps in dose-related manner. After infection with Aer. hydrophila, survivals of fish fed with 4 and 8% L. cubeba doses were significantly higher than those fed with 2% dose and the control.

SIGNIFICANCE AND IMPACT OF THE STUDY

A range of 4-8% L. cubeba leaf powder supplementation diet (from specific linalool-rich chemotype) can be used in aquaculture to reduce antibiotic burden and impacts of diseases caused by Aer. hydrophila.

Cytotoxicity potentials of eleven Bangladeshi medicinal plants

Various forms of cancer are rising all over the world, requiring newer therapy. The quest of anticancer drugs both from natural and synthetic sources is the demand of time. In this study, fourteen extracts of different parts of eleven Bangladeshi medicinal plants which have been traditionally used for the treatment of different types of carcinoma, tumor, leprosy, and diseases associated with cancer were evaluated for their cytotoxicity for the first time. Extraction was conceded using methanol. Phytochemical groups like reducing sugars, tannins, saponins, steroids, gums, flavonoids, and alkaloids were tested using standard chromogenic reagents. Plants were evaluated for cytotoxicity by brine shrimp lethality bioassay using Artemia salina comparing with standard anticancer drug vincristine sulphate. All the extracts showed potent to moderate cytotoxicity ranging from LC50 2 to 115 µg/mL. The highest toxicity was shown by Hygrophila spinosa seeds (LC50 = 2.93 µg/mL) and the lowest by Litsea glutinosa leaves (LC50 = 114.71 µg/mL) in comparison with standard vincristine sulphate (LC50 = 2.04 µg/mL). Among the plants, the plants traditionally used in different cancer and microbial treatments showed highest cytotoxicity. The results support their ethnomedicinal uses and require advanced investigation to elucidate responsible compounds as well as their mode of action.

Karen and Lawa medicinal plant use: uniformity or ethnic divergence?

ETHNOPHARMACOLOGICAL RELEVANCE

We here tease apart the ethnopharmacological knowledge of plants in two Thai villages to determine to which degree the uses are particular to individual ethnic groups and to which degree they are part of a generalized and uniform set of widespread medicinal plants used over a large geographic range. We compared Karen and Lawa knowledge of medicinal plants in the Mae Cheam watershed of northern Thailand, where both ethnic groups have settled and share ecological conditions for resource extraction. We were interested in documenting the degree to which these two ethnic groups use the same or different medicinal plant species. The use of the same plant species by the two groups was considered a sign of uniform and cross-cultural local knowledge, whereas the use of different medicinal plants by each group was considered a sign of culturally specific local knowledge that developed within each ethnic group.

MATERIALS AND METHODS

We inventoried the plant species in different habitats around one Karen village and one Lawa village using stratified vegetation plots and using semi-structured questionnaires we interviewed 67 key informants regarding their use of plants for medicine. We then calculated the Fidelity level FL (FL values near 100% for a species indicate that almost all use reports refer to the same way of using the species, whereas low FL values indicate that a species is used for many different purposes) and cultural importance index CI (the sum of the proportion of informants that mention each of the use categories for a given species) to estimate the variation in medicinal plant use. We used Jaccard's Index JI (This index relates the number of shared species to the total number of species) to analyze the similarity of medicinal plant use between the two villages.

RESULTS

A total of 103 species of medicinal plant species in 87 genera and 41 families were identified and they were used to cure 35 ailments. The FL of the medicinal plant species varied from 10% to 100%, was different for each ailment, and differed between the two ethnic groups. The most important medicinal plant species, those with the highest CI value, were not the same in the two villages. Costus speciosus, which is used to treat urinary infections and wounds in animals, had the highest CI value in the Karen village, whereas Sambucus javanica, which is used to treat wounds, fractures, bloat, and edema in humans, had the highest CI value in the Lawa village. Only 17 medicinal species (16.5%) were shared between the two villages. Methods of preparation and application were significantly different between the two villages, whereas the plant parts used, habit, and route of administration were similar.

CONCLUSION

Our study demonstrates that ethnic groups that live in the same geographic area can have significantly different traditional knowledge systems for medicinal plants, at least when it comes to the species used and their preparation and medicinal application. We assume that differences in cultural history and background in the two villages led to differences in medicinal plant use, preparation, and application.