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Two new iridoid glycosides, named 6 β - O -methyl-unedoside ( 1 ) and 6 β - O -methyl-5-deoxythunbergioside ( 2 ) along with two known phenyl propanoid glucoside compounds dolichandroside A ( 3 ) and verbascoside ( 4 ) were isolated from the aerial parts of Odontonema cuspidatum (Nees) Kuntze (Acanthaceae). Structure elucidation of the new compounds was established by interpretation of their 1D and 2D-NMR spectral data by comparing with literatures, HRESIMS and optical activity measurement. The isolated compounds were tested for their in vitro antimicrobial and antimalarial activities. Compound 4 showed a moderate antimicrobial activity against E. coli with IC 50 value of 17.5 μM in comparing with Vancomycin and Cefotaxime.

Summary A new species, Odontonema peruvianum J.R.I.Wood is described and illustrated. This represents the most southerly extension in the range of the genus and the first confirmed record of its occurrence as a native in Peru.

Odontonema guayaquilense, a new species of subshrub of Acanthaceae from the remnant deciduous dry forests of Guayaquil, in coastal Ecuador, is here described and illustrated. The new species is assessed as Endangered EN B1ab(iii).

A new species of Oplonia from the province of Jujuy, Argentina, 0. jujuyensis, is de- scribed, illustrated, and compared with its closest relative. It differs markedly from 0. hutchisonii by the corolla, which is weakly zygomorphic, and by the erect limb, with the posterior lip deeply two- lobed. This is the first report of this genus from Argentina. The present study of the Acanthaceae for the flora of the Province of Jujuy, Argentina, has led to the recognition of a new species of Oplonia from that region. The genus belongs to the subfamily Acanthoideae tribe Odontonemeae in accordance with Lindau's (1895) infrafamilial classification of the Acanthaceae, or in the tribe Justicieae subtribe Odontoneminae if one prefers to follow Breme- kamp's (1965) system of subfamilial classification. It is characterized by flowers that are either solitary in the leaf axils or borne in comparatively few- flowered axillary fascicles with minute bracts. This much reduced inflorescence distinguishes Oplonia from Odontonema Nees, the latter of which has flowers borne in terminal racemes or panicles. The corolla is zygomorphic, occasionally only weakly so, with a slender tube and a two-lipped limb, the pos- terior lip is two-lobed and the anterior lip is three- lobed. There are two stamens, which may be ex- serted or included, and two staminodes. Presently, two species are known from northern Peru, eight from the West Indies, and five from Madagascar. This is the first time that the genus is reported from Argentina. Although the genus Oplonia is easily recognized and defined, the delimitation and distribution of the taxa are more complex and somewhat unusual. Most species grow in dry open habitats as part of scrub forest. The new taxon is found in thicket of tran- sitional forest between the Chaco and Yungas (sensu Cabrera, 1976). The evolution of the genus (Stearn, 1971) would appear to be from a mesophytic spine- less South American ancestor, resembling the small- flowered species of Odontonema, by progressive re- duction in leaf size, by the contraction of the inflo- rescence from a narrow panicle or raceme into a few-flowered axillary fascicle or solitary flower, and by the conversion of lateral branches into spines, by which changes they became xerophytic. We be- lieve that Oplonia jujuyensis, with its reduced leaves, an inflorescence of few flowers in axillary fascicles, small, Odontonema-like flowers, and habitat rep- resents an isolated transition between the genera Odontonema and Oplonia.

Pulchranthus (Acanthaceae: Acanthoideae) is established for a series of species once referred to Odontonema or Pseuderanthemum. Four species are assigned to the genus: P. surinamensis (the type species) from Surinam, P. adenostachyus from Peru, southern Colombia, and western Brazil, P. variegatus from French Guiana and adjacent northeastern coastal Brazil, and P. congestus from the states of Amazonas and Para, Brazil. Pulchranthus is clearly related to Odontonema but differs in having a well-developed bilabiate, curved, white to violet corolla with dark purplish dots on the lobes, exserted and curved filaments, and glandular-puberulent rachises. In Odontonema the corollas are tubular, red or white to yellow or rarely purplish, and only weakly bilabiate, the filaments are straight and short with anthers usually included in the corolla tube, and the rachises of the inflorescences vary from glabrous to tomentose or rarely glandular. In Pseuderanthemum the flowers are narrowly salverform with a slender tube and a regular corolla. During the course of a revision of the Neo- tropical Odontonema Nees, nom. cons. prop. (Baum and Reveal 1980), specimens of 0. suri- namense Bremekamp (1938) were set aside be- cause they did not represent the typical expres- sion of Odontonema. Bremekamp had noted that the genus seemed to comprise "two sections which, probably, might be raised to generic rank: one with tubiform, subregular, red flow- ers in dense and very narrow panicles; the oth- er with deeply bilabiate white or slightly col

Six new species ofOdontonema are described:Odontonema album, O. amicorum, O. breedlovei, O. laxum, O. mortonii andO. speciosum. In addition two new combinations are proposed forOdontonema,O. glaberrimum andO. nitidum var.album, and nine species are transferred fromOdontonema to other acanthaceous genera, namelyAnisacanthus ramosissimus, Buceragenia foliaceo-bracteata, Pseuderanthemum cuspidatum, P. hookerianum, P. interruptum, P. paniculatum, P. stenostachyum, Stenostephanus longistaminus andStreblacanthus dubiosus.