Abstract. Lepcha DL, Pradhan A, Chhetri DJ. 2019. Population assessment and species distribution modeling of Paris polyphylla in Sikkim Himalaya, India. Biodiversitas 20: 1299-1305.  Paris polyphylla Smith is an important therapeutic plant that grows in the Indian Himalayan region. In Sikkim, the survival of the species is threatened by illegal extraction of its rhizome. Therefore, immediate conservation initiative is required to conserve the existing species population in the wild. Population assessment through field survey followed by ENM revealed a positive correlation between predicted suitable habitats with the actual sites of its occurrence, except in disturbed habitats. Precipitation of driest month (Bio14) and slope were the most influential factors that contributed 41.9 % and 30 % respectively to the MaxEnt model. Field survey revealed that the density of the plants varied between 0.45 (pl/m2) and 3.89 (pl/m2) and the frequency varied from 36% to 76%. The IVI for P. polyphylla ranged between 2.68 to 8.66 based on locations. On the other hand, the IVI of associated species varied from 3.57 to 18.14 based on species. P. polyphylla is a vulnerable plant in Sikkim Himalaya and it is facing an imminent threat of extinction. Under this situation, it is imperative that works on predictive modeling will help conserve the species. This study identified the potential habitats for P. polyphylla in the higher elevations of Sikkim Himalaya where it could be reintroduced.

Introduction: Paris polyphylla Smith is a high value medicinal plant available in Sikkim Himalaya which is well known in local traditional medicine system. Scientific study to ascertain its claimed biological activity is lacking. The objective of this work was to determine the antioxidant and anticancer activity of Paris polyphylla rhizomes. Methods: Phytochemical analysis were carried out by standard methods. Antioxidant activity of the methanolic extract was carried out by DPPH, ABTS, OH-radical and Fe 2+ chelating activity assays. Cytotoxicity of the extract was determined by MTT assay on three cancer cell lines: HeLa, HepG2 and PC3. Results: Of the P. polyphylla from two altitudinal zones, P. polyphylla from Tholung (PPT), the one from the higher altitude showed higher total phenolic contents in methanolic extracts of rhizomes as compraed to that from the lower altitude i.e., P. polyphylla from Uttaray (PPU). PPT also showed a higher content of total falvonoid and total flavonols. Both types of plant were excellent scavenger of DPPH and ABTS radical and Fe 2+ chelator. A trend of a relatively greater antioxidant activity of PPT was established through these assay methods. In MTT assay, both the extract showed significant dose-dependent inhibition of HeLa cell growth after 72 hrs of treatment, while the extract had a moderately positive effect on the inhibition of PC3 and HepG2 cells growth. Conclusion: The study suggested a strong antioxidant activity and appreciable cytotoxic activity of P. polyphylla from Sikkim Himalaya. Of the two varieties, PPT was more pronounced in both type of activities.