Further fragmentation of the polyphyletic genusPolyalthia(Annonaceae): molecular phylogenetic support for a broader delimitation ofMarsypopetalum

Chemical constituents of the stem of Marsypopetalum modestum and their bioactivities

Phytochemical investigation of Marsypopetalum modestum (Annonaceae) led to the isolation of a new phenylpropanoid glycoside, lyciumphenylpropanoid B (10), along with nine known compounds (1-9) from an aqueous methanolic extract of the stem. Most compounds are reported from this genus for the first time. The structures of the isolated compounds were elucidated using spectroscopic methods including NMR spectroscopy, high-resolution mass spectrometry, and quantum chemical electronic circular dichroism (ECD) calculations. Cytotoxic and antitubercular activities of several isolated compounds were evaluated. Dipyrithione (1) displayed anti-mycobacterial (MIC = 0.23 μM) and cytotoxic (IC50 = 0.8 μM in Hep G2 cells; 4.1 μM in HCT 116 cells) activities. Kelampayoside A (8) showed moderate cytotoxic activity against cancer cells.

Phylogenetic relationships of 'Polyalthia' in Fiji

The genus Polyalthia (Annonaceae) has undergone dramatic taxonomic changes in recent years. Nine Polyalthia species have historically been recognized in Fiji, all of which have subsequently been transferred to three different genera, viz. Goniothalamus, Huberantha and Meiogyne. The transfer of six of these species has received strong molecular phylogenetic support, although the other three species, Polyalthia amoena, P. capillata and P. loriformis [all transferred to Huberantha], have never previously been sampled in a phylogenetic study. We address this shortfall by sampling available herbarium specimens of all three species and integrating the data in a molecular phylogenetic analysis. The resultant phylogeny provides strong support for the transfer of these species to Huberantha. The taxonomic realignment of all nine Fijian species formerly classified in Polyalthia is also clearly demonstrated and supported by the resultant phylogeny. The updated taxonomic treatments of the nine species, a key to the three genera and a key to the Fijian Huberantha species are provided.

From Polyalthia to Polyalthiopsis (Annonaceae): transfer of species enlarges a previously monotypic genus

The genus Polyalthiopsis Chaowasku (Annonaceae) was a poorly known monotypic genus from Vietnam that was recently segregated from the highly polyphyletic genus Polyalthia s.l. The sister clade relationship between Polyalthiopsis and Miliusa was not well established in previous study. The phylogenetic position of two Polyalthia spp. from China, P. chinensis S.K.Wu ex P.T.Li and P. verrucipes C.Y.Wu ex P.T.Li, remains unresolved and is shown here to be phylogenetically affiliated with Polyalthiopsis. Phylogenetic analyses of six chloroplast regions (matK, ndhF, psbA-trnH, rbcL, trnL-F and ycf1; ca.7.3 kb, 60 accessions) unambiguously placed Polyalthia chinensis and P. verrucipes in the same clade with Polyalthiopsis floribunda (PP = 1, MPBS = 97%); the entire clade is sister to Miliusa with weak to strong support (PP = 1, MPBS = 54%). Polyalthia chinensis and P. verrucipes share several diagnostic characters with Polyalthiopsis floribunda, including the raised midrib on the upper surface of the leaf in vivo, conspicuous foliar glands when dried, petiole with transverse striations when dried and axillary inflorescences. The two species differ from Polyalthiopsis floribunda in having fewer flowers per inflorescence, longer linear petals and two ovules per carpel. On the basis of the combined molecular phylogenetic and morphological data, we propose two new combinations, Polyalthiopsis chinensis (S.K.Wu ex P.T.Li) B.Xue & Y.H.Tan and Polyalthiopsis verrucipes (C.Y.Wu ex P.T.Li) B.Xue & Y.H.Tan. The protologue of Polyalthia verrucipes did not include a description of the flowers, which we provide here. An updated description for the genus Polyalthiopsis and a key to species in the genus Polyalthiopsis is also provided.

Two new species of Trivalvaria (Annonaceae) from northern Myanmar

Trivalvaria rubra and Trivalvaria casseabriae, two new species of Annonaceae from Putao, Kachin State, Myanmar, are here described and illustrated. They are morphologically similar to T. costata and T. macrophylla. The major differences between them are outlined and discussed. A diagnostic key to the species of Trivalvaria is provided.

Phylogenetic analyses and morphological characteristics support the description of a second species of Tridimeris (Annonaceae)

Based on phylogenetic and morphological evidence, Tridimeris chiapensis Escobar-Castellanos & Ortiz-Rodr., sp. n. (Annonaceae), a new species from the karst forest of southern Mexico, is described and illustrated. The new species differs from Tridimeris hahniana, the only described species in the genus, in that the latter has flowers with sepals densely tomentose outside, one (rarely two) carpel(s) per flower and fruits densely covered with golden-brown hairs, while Tridimeris chiapensis has flowers with glabrous sepals outside, two to five carpels per flower and glabrous fruits. Furthermore, a shallow triangular white patch at the base of the inner petals is found in Tridimeris chiapensis, a morphological character shared with the sister genus Sapranthus but absent in Tridimeris hahniana. Geographically, both species occur allopatrically. With just one known locality and seven individuals of Tridimeris chiapensis recorded in one sampling hectare, and based on application of the criteria established by the IUCN, we conclude tentatively that the species is critically endangered.

A plastid DNA phylogeny of tribe Miliuseae: insights into relationships and character evolution in one of the most recalcitrant major clades of Annonaceae

PREMISE OF THE STUDY

Tribe Miliuseae (∼25 genera and ∼510 species) includes a substantial part of the species and generic diversity in the pantropical flowering-plant family Annonaceae (∼108 genera and ∼2400 species). Previous molecular phylogenetic analyses have failed to resolve the backbone phylogeny of the tribe, impeding biogeographical and evolutionary studies. We use a dense generic taxon sample (∼89% of generic diversity in Miliuseae) and plastid DNA sequence data (∼7 kb) to clarify the phylogenetic relationships of and within the tribe.

METHODS

Parsimony and Bayesian phylogenetic reconstructions and ancestral character-state reconstructions of several reproductive characters were performed.

KEY RESULTS

Dendrokingstoniae, Monocarpieae, and Miliuseae are recovered in a strongly supported clade, and each tribe is strongly supported as monophyletic. Miliuseae are characterized by a synapomorphic cryptoaperturate/disulculate pollen apertural system. Stenanona is shown to be nested within the paraphyletic genus Desmopsis. The only Neotropical clade (Sapranthus, Tridimeris, Desmopsis, and Stenanona) in the predominantly Asian Miliuseae is shown to be closely related to an undescribed genus from continental Southeast Asia and the Indo-Malayan and Austral-Pacific genus Meiogyne. Ancestral character-state reconstructions of several reproductive characters that are diagnostically important at the generic level indicate a considerable degree of homoplasy.

CONCLUSIONS

The results improve our understanding of the relationships of and within Miliuseae, but parts of the backbone of the phylogeny remain poorly supported. Additional data from variable nuclear markers or reduced-genome-representation approaches seem to be required to further resolve relationships within this recalcitrant clade.

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.

Reassessing morphological homologies in the early-divergent angiosperm Fenerivia (annonaceae) based on floral vascular anatomy: significance for interpreting putative homeotic mutations

Fenerivia species (Annonaceae) are characterized by a prominent flange immediately below the perianth, which has been interpreted as synapomorphic for the genus. The homology of this flange is controversial: previous studies of Fenerivia heteropetala (an aberrant species, with 12 perianth parts in three whorls) have suggested that the flange may represent a vestigial calyx resulting from a disruption to the homeotic control of organ identity during floral development. Comparative data on floral vasculature in Fenerivia capuronii are presented to elucidate the homology of the flange in other Fenerivia species (which possess nine perianth parts in three whorls, typical of most Annonaceae). The flange in F. capuronii differs from that in F. heteropetala as it is unvascularized. It is nevertheless suggested that the flange is likely to be homologous, and that a homeotic mutation in the F. heteropetala lineage resulted in the formation of a vestigial but vascularized calyx that fused with the otherwise unvascularized flange.

A new species of Goniothalamus (Annonaceae) from Palawan, and a new nomenclatural combination in the genus from Fiji

A new species, Goniothalamus palawanensis C.C.Tang & R.M.K.Saunders, sp. nov. (Annonaceae), is described from Palawan, Philippines. Goniothalamus palawanensis is most closely related to Goniothalamus amuyon (Blanco) Merr., but differs in its shorter inner petals, hairy ovaries, and funnel-shaped stigmas. A new nomenclatural combination, Goniothalamus angustifolius (A.C.Sm.) B.Xue & R.M.K.Saunders, comb. nov., is furthermore validated to reflect the phylogenetic affinities of a Fijian species previously assigned to Polyalthia.