Three new species of Elatostema (Urticaceae) from Thailand

Three new species of Elatostema (Urticaceae) from Thailand, E.kaweesakii Triyutth. & L.F.Fu, sp. nov., E.rubricaule Triyutth. & L.F.Fu, sp. nov. and E.saxatile Triyutth. & L.F.Fu, sp. nov., are newly described and illustrated. These new species can be distinguished by the presence of rhizome. Elatostemakaweesakii is similar to E.atroviride. Elatostemakaweesakii is a lithophyte growing in limestone crevices. It differs from E.atroviride by its large swollen rhizome, glabrous stem, glabrous receptacle, number of tepal in staminate flower, absence of tepal in pistillate flower, presence of staminodes in pistillate flower and smooth achene. Elatostemarubricaule and E.saxatile are found on sandstone habitats. They have distinct flattened and disk-like rhizome. Elatostemarubricaule is distinguished by its distinct sulcate and reddish stem with flattened and disc-like rhizome and chartaceous leaves with entire margin. Elatostemasaxatile resembles E.bulbiferum but differs by its flattened and disc-like rhizome, acute leaf apex, glabrous receptacle in pistillate inflorescences, presence of staminodes in pistillate flower, and its sandstone habitat. Descriptions, distribution, ecological and phenological data are provided.

Cytotoxic and α-glucosidase inhibitory metabolites from twigs and leaves of Phyllanthus mirabilis, a species endemic to limestone mountains

The first investigation of Phyllanthus mirabilis Müll.Arg. led to the isolation of six undescribed compounds including two tyramine derivatives: phyllatyramines A and B; three butenolide analogues, phyllantenolide, phyllantenocoside-O-gallate and epi-phyllantenocoside-O-gallate; and a flavanonol gallate, (-)-taxifolin-3-O-gallate; as well as two first isolated natural products, phyllatyramine C and phyllantenocoside; together with twenty-three known compounds. Their structures were elucidated by spectroscopic means. ECD spectra of all isolated butenolides were compared and assigned the configurations. Phyllatyramine A displayed weak cytotoxicity against the KB cell line, while phyllatyramines B and C showed weak cytotoxicity against KB and HeLa cell lines. In addition, phyllatyramine B and (-)-taxifolin-3-O-gallate showed more potent α-glucosidase inhibitory activity than the standard acarbose 3.4 and 5.8 fold, respectively.

Inter-primer binding site (iPBS) markers reveal the population genetic diversity and structure of tropical climbing Cissampelopsis (Asteraceae) in Thailand

Abstract. Vanijajiva O, Pornpongrungrueng P. 2020. Inter-primer binding site (iPBS) markers reveal the population genetic diversity and structure of tropical climbing Cissampelopsis (Asteraceae) in Thailand. Biodiversitas 21: 3919-3928. Cissampelopsis is a small climbing tropical Asian genus of Asteraceae-Senecioneae. In Thailand, the genus is represented by two species, C. corifolia and C. Volubilis, distributed through the mountain evergreen forest. Study on the genetic diversity and structure of populations of both Cissampelopsis species provide better understanding of the biology and pattern of species diversification in the genus. To identify the genetic diversity, we used the inter-primer binding site (iPBS) retrotransposon system, in 96 accessions of Cissampelopsis species collected from different regions in Thailand. A total of 120 iPBS bands were scored as presence⁄ absence characters. Results from UPGMA and PCoA analyses indicated that C. corifolia and C. volubilis are different species. Genetic diversity and genetic differentiation among and within populations of C. volubilis is higher than C. corifolia. Molecular Variance (AMOVA) analysis of both species indicated that the genetic variance value within populations is higher than among populations of each species. Bayesian model-based STRUCTURE analysis detected two gene pools for both Cissampelopsis and showed admixture within individuals. Differences among the two Cissampelopsis species, in total diversities and levels of population differentiation, indicated that the genetic structure of Cissampelopsis populations are congruent with long-lived perennial habit with regional distribution, even for congeneric species, may vary considerably. This study suggests the effectiveness of the iPBS marker system to estimate the population genetic diversity and structure of Cissampelopsis genotypes.

Two new species of Phyllanthus (Phyllanthaceae) from Thailand

Two Phyllanthus species are newly described from a limestone mountain in the north of Thailand. The first species, P. huamotensis Pornp., Chantar. & J.Parn., sp. nov., is one of the most distinct Phyllanthus species easily distinguished by its reddish branchlets and stem, conspicuous reddish venation, especially on the lower leaf surface, red sepals with long fimbriate margin and red capsule with papillose-puberulous surface. The second species, P. chantaranothaii Pornp., J.Parn. & Hodk., sp. nov., is similar to P. pulcher Wall. ex Müll.Arg., but it is distinguished by its puberulous upper leaf surface and pistillate flowers which have red, narrowly lanceolate sepals with a white, long fimbriate margin, puberulous outer side as well as puberulous pedicel.