a-Bin Hu

Environmental and Socioeconomic Impacts of Increasing Rubber Plantations in Menglun Township, Southwest China

Abstract Significant changes in land use and land cover have occurred in Menglun Township, Xishuangbanna Autonomous Prefecture, southwest China. This is a region of high agro-ecological diversity representative of the general biophysical and socioeconomic conditions of Xishuangbanna. An analysis of satellite images showed that from 1988 to 2003, rubber plantations increased by 324%; this expansion generally occurred at the expense of forests and shifting agriculture. Most rubber expansion was in the lowland areas, where suitable microclimates and proximity to roads favored the development of the rubber industry. Economically, all the villages showed an improved living standard; from 1988 to 2003, the total net income of the township increased from CNY 4 million (US

Limonoids from the Leaves and Twigs of Walsura yunnanensis.

0.49 million) to CNY 44 million (US

Koumine, Humantenine, and Yohimbane Alkaloids from Gelsemium elegans

5.49 million). The increasing population and rising living standard of the area will put greater pressure on the environment and available land resources. Although the government considers rubber and other plantations such as tea and sugar to be ‘green industries,’ the loss of tropical rainforest and agricultural lands (including diverse shifting agriculture) suggests that the potential impacts of policies to promote green industries should be considered carefully. Communities such as those in northern Laos, where the rubber industry is now expanding rapidly, are likely to experience a similar scenario.

Chemical composition, antimicrobial and anti-inflammatory activities of the essential oil from Maqian (Zanthoxylum myriacanthum var. pubescens) in Xishuangbanna, SW China.

Nine new cedrelone limonoids, namely, walsuranolide B (1), 11β-hydroxy-23-O-methylwalsuranolide (2), yunnanolide A (3), yunnanol A (4), 11β-hydroxyisowalsuranolide (5), 11β-hydroxy-1,2-dihydroisowalsuranolide (6), 1α,11β-dihydroxy-1,2-dihydroisowalsuranolide (7), 11β-hydroxy-1α-methoxy-1,2-dihydroisowalsuranolide (8), and yunnanolide B (9), together with a new cycloartane triterpenoid, (24S*,25R*)-cycloartane-3β,24,25,26-tetrol (10), were isolated from the leaves and twigs of Walsura yunnanensis. Their structures were elucidated on the basis of spectroscopic analysis and by comparison with literature data. Compounds 3 and 5 exhibited potent cytotoxicity against five human tumor cell lines with IC50 values in the range 2.2-4.2 μM.

Gelsemium alkaloids, immunosuppressive agents from Gelsemium elegans

Nine new alkaloids of the koumine (1-4), humantenine (5-7), and yohimbane (8, 9) types as well as 12 known analogues were isolated from the leaves and vine stems of Gelsemium elegans. Compound 1 is the first N-4-demethyl alkaloid of the koumine type, compound 7 is the first nor-humantenine alkaloid, and compounds 8 and 9 are the first N-1-oxide and the first seco-E-ring alkaloids, respectively, of the yohimbane type. Compounds 1 and 7 exhibited moderate cytotoxicity against five human tumor cell lines with IC50 values in the range 4.6-9.3 μM.

Cytotoxic limonoids from Trichilia americana leaves

ETHNOPHARMACOLOGICAL RELEVANCE Maqian (Zanthoxylum myriacanthum var. pubescens Huang) is widely consumed as an indigenous remedy for digestive disorders, detoxification, detumescence and analgesia by the ethnic groups in Xishuangbanna, SW China. A related species, Huajiao (Zanthoxylum schinifolium Sieb. et Zucc.), has similar uses in traditional Chinese medicine. We aimed to scientifically validate the traditional uses by investigating and comparing the chemical composition, antimicrobial and anti-inflammatory activities of the essential oils of Maqian and Huajiao. MATERIALS AND METHODS Essential oils were collected from the fruits of Maqian and Huajiao by simultaneous distillation extraction and identified by gas chromatography-mass spectrometry (GC-MS) analysis. To assess antimicrobial activity, the minimum inhibitory and bactericidal concentrations (MIC and MBC) against 7 microbial strains, including 5 food-borne pathogens, were evaluated by serial dilution with a standardized microdilution broth methodology. For anti-inflammatory activity, the cell viability and nitric oxide (NO) production were determined on lipopolysaccharide (LPS)-stimulated RAW 264.7 cells by MTS assay and the Griess reagent system, respectively. RESULTS The essential oil from Maqian is rich in limonene (67.06%) and has strong antimicrobial activity against the tested pathogens and spoilage organisms, with MIC ranging from 64 to1024µg/ml and MBC ranging from 64 to 2048µg/ml. It also showed anti-inflammatory activity by significantly inhibiting nitric oxide (NO) production induced by LPS in RAW 264.7 cells at 0.04‰ without effects on cell viability. Furthermore, it showed relatively stronger antimicrobial and anti-inflammatory activities than the essential oil from Huajiao. CONCLUSIONS Our findings not only justify the use of Maqian as an indigenous remedy for digestive disorders, detoxification, detumescence and analgesia, but also suggest that it could be promoted as a preferred substitute for Huajiao.

Rain forest dwellers' livelihoods: income generation, household wealth and NTFP sales, a case study from Xishuangbanna, SW China

Bioassay-guided isolation of the stems of Gelsemium elegans has led to the isolation of two new Gelsemium alkaloids, 21-(2-oxopropyl)-koumine (1) and 11-methoxygelselegine (2), and two known alkaloids, koumine (3) and gelselegine (4). The structures of 1-2 were determined by spectroscopic (for both) and single-crystal X-ray diffraction (for 1) analysis. All compounds isolated were evaluated for their potential as immunosuppressive agents and the data suggested that Gelsemium alkaloids of different structural types possibly have potential as immunosuppressive agents.

Limonoids from the Fruits of Khaya ivorensis

Ten cedrelone limonoids were isolated from the leaves of Trichilia americana. These compounds include americanolides A-D (1-4), 1,2-dihydrodeacetylhirtin (5), 1α-hydroxy-1,2-dihydrodeacetylhirtin (6), 1α-hydroxy-1,2-dihydrohirtin (7), 1α-methoxy-1,2-dihydrodeacetylhirtin (8), 11β-hydroxy-12α-propanoyloxycedrelone (9), and 1α,11β-dihydroxy-1,2-dihydrocedrelone (10), as well as two previously reported compounds, deacetylhirtin (11) and hirtin (12). Their structures were characterized on the basis of spectroscopic studies, and the assignment of the absolute configuration of americanolide A (1) was supported by single-crystal X-ray diffraction studies. The cytotoxic activities of all isolated compounds were also evaluated against five human tumour cell lines (HL-60, SMMC-7721, A-549, MCF-7, and SW-480) using an MTS assay. Compounds 11 and 12 showed significant cytotoxicity with IC50 values ranging from 0.1 to 0.5 μM, and compounds 5, 6, 7, 8, 9, and 10 exhibited potent or selective cytotoxic activity with IC50 values ranging from 1.0 to 39.6 μM.

Chemical constituents and anti-inflammatory activities of Maqian ( Zanthoxylum myriacanthum var. pubescens ) bark extracts

Through annual in-depth household questionnaire interviews of 60% of households in Daka and Baka villages from 1998 to 2004, we explored wealth-related differences and similarities in the sale of NTFPs of tropical rain forest fringe dwellers in Xishuangbanna, SW China. Contribution of different NTFPs to cash income and different seasonal access to NTFPs between Baka and Daka were analysed. There were significant differences in income and role of NTFPs per household between Baka and Daka related to different access to: NTFPs in forests, labour and market sales in different seasons. In Baka, the ranking of NTFP income was: fungi, wild vegetables, bamboo shoot in 2000 and 2001. Differences in gender and generational involvement in NTFP sales was also examined. For example, households without a son, as well as those with a female householder depended more on income from NTFPs and less on income from rubber than other households. Resource use patterns between relatively wealthy and poor households were also analysed. Wealthy households sold 2.50 ± 0.50 types while poor households sold 2.08 ± 0.26 NTFPs. The Gini coefficient of gross income per household for Baka in recent years was 0.393, increasing to 0.414 without NTFPs. The Gini coefficient of gross income for Daka in recent years was 0.291, increasing to 0.292 without NTFPs, showing the different role of NTFPs in mitigating wealth inequality in the two villages.

An ethnobotanical study of the less known wild edible figs (genus Ficus) native to Xishuangbanna, Southwest China

Two new limonoids, namely 14,15-didehydroruageanin A (1) and 3-O-methyl- butyrylseneganolide A (2), were isolated from the fruits of Khaya ivorensis along with six known limonoids: seneganolide A (3), 1,3-dideacetylkhivorin (4), 7-deacetylkhivorin (5), 3-deacetylkhivorin (6), 1-deacetylkhivorin (7), and 3-deacetyl-7-oxokhivorin (8). All the compounds were evaluated for their cytotoxicity against five tumor cell lines.