An A-ring contracted triterpenoid from Hyptis suaveolens

The abundance of adventitious-root-climbing vines, predominantly Freycinetia excelsa and Piper caninum, on potential host trees was investigated in a north Queensland tropical rain forest. All trees 10 cm DBH and greater were measured and assessed for adventitious-root-climber presence. Additional trees of the 17 most abundant species were examined giving a total of 833 trees. Some 1694 adventitious-root-climbing vines were recorded from the study area. Distribution over the rain forest trees was not homogeneous, but exhibited host associations. Interspecific differences between potential host trees were analyzed in terms of allelopathy, bark characteristics, and gross morphological features. Bark characteristics are proposed. as the main factor for the relative absence of adventitious-root-climbing vines on trees of Syzygium papyraceum and Austromyrtus shepherdii. Thin, peeling, sloughable bark characterize these members of the Myrtaceae. Trees heavily infested by adventitious-root climbers include Beilschmiedia collina with non-descript (though slightly rough) bark providing a good, stable climbing surface with little phytotoxicity, and Citronella smythii, with thick, corky, fissured bark, also lacking allelopathic materials. Allelopathic effects of bark phytochemicals seem to be predominantly responsible for the absence of infestation of Alphitonia petriei by adventitious-root climbers.

Host associations of two adventitious-root-climbing vines in a north queensland tropical rain forest

Biosurfactant from red ash trees enhances the bioremediation of PAH contaminated soil at a former gasworks site

Introduction

Alphitonia neocaledonica (Rhamnaceae) is an endemic tree of New Caledonia. Although three flavonoids have been identified in the leaves, the secondary metabolite profile of the fruits has never been investigated.



Objective

Phytochemical investigation of A. neocaledonica fruits and evaluation of their anti-oxidant, anti-tyrosinase and cytotoxic activities.



Methods

A hydromethanolic extract was fractionated by liquid–liquid extraction to obtain ethyl acetate and n-butanolic fractions. The ethyl-acetate-soluble part was purified by silica-gel column chromatography and high-performance liquid chromatography (HPLC). The n-butanol-soluble part was fractionated by centrifugal partition extraction (CPE) and the collected fractions were further purified by centrifugal partition chromatography (CPC) and HPLC. The chemical structures of the purified compounds were identified by nuclear magnetic resonance and mass spectrometry.



Results

Three triterpenoids and one flavonoid were isolated from the ethyl-acetate-soluble part. Fractions enriched in triterpenoids, flavonoids and catechin derivatives were obtained from the n-butanol-soluble part. Gallocatechin and flavonoids were obtained as pure compounds by further CPC and HPLC purification. The n-butanolic-soluble part showed anti-oxidant and anti-tyrosinase activities due to the presence of tannins and gallocatechin. The triterpenoid alphitolic acid showed a moderate cytotoxic activity against KB cell line (median inhibition concentration = 8.5 μM).



Conclusions

Nine known compounds including three triterpenes, five flavonoids and (+) gallocatechin, as well as a new 3-O-(6-E-feruloyl)-β-D-glucopyranosyl-(1  2)-[β-D-xylopyranosyl-(1  2)-]α-L-rhamnopyranosyl-quercetin, were isolated from A. neocaledonia fruits. The hydromethanolic extract possesses a potential cytotoxic activity due to the presence of triterpenes, and it can also be valuable as a cosmetic ingredient for its anti-oxidant and anti-tyrosinase activities. Copyright © 2014 John Wiley & Sons, Ltd.

/pdf/isolation-of-flavonoids-and-triterpenoids-from-the-fruits-of-3u4fscx2ix.pdf

Isolation of flavonoids and triterpenoids from the fruits of Alphitonia neocaledonica and evaluation of their anti-oxidant, anti-tyrosinase and cytotoxic activities.

This study examined the effects of insect herbivory on growth and mortality of seedlings of a mid- successional rainforest tree, Alphitonia whitei Braid. Two experiments were conducted in which seedlings were exposed to 0% and 50% natural defoliation by insect herbivores and placed in light gaps in simple notophyll vine forest at Paluma, near Townsville, North Queensland. In the first experiment, insect herbivory significantly increased mortality of 2-month-old seedlings. Smaller seedlings had significantly greater mortality rates than larger seedlings, irrespective of herbivory. A significantly greater proportion of smaller seedlings died from being smothered by fallen leaves and soil as a result of digging by vertebrates than for larger seedlings. In the second experiment, the effects of seedling age were examined by comparing 2-month and 4-month-old seedlings. Mortality rates were significantly influenced by seedling age, with eight times greater survival of older seedlings than of younger seedlings. Although insect herbivory was correlated with a significant decrease in shoot mass and a significant increase in root:shoot ratio, there was no effect of insect herbivory on seedling survival in the second experiment. Thus, mortality rates were greater for seedlings if they were young or small (which indirectly results from insect herbivory), because small, young seedlings were more susceptibile to other mortality factors, such as burial by fallen debris and digging by vertebrates.

Effects of herbivory on growth and survival of seedlings of a rainforest tree, Alphitonia whitei (Rhamnaceae)

The extractives of the barks and leaves of Alphitonia excelsa, A. petriei, and A. whitei, and of the wood, bark, and leaves of A. macrocarpa have been examined. Ceanothic, betulinic, and alphitolic acids were isolated from all species, but A. macrocarpa was exceptional in that its wood contained no benzylhydroxycoumarone derivative, characteristic of the other species, and its leaves gave a small yield of the alkaloid, adouetine X. From the bark of A. excelsa a new triterpene, alphitexolide, was isolated in very small amount. By spectroscopic methods and a partial synthesis its structure was established as(1).

Constituents of Alphitonia Species. III. Alphitexolide, a New Triterpene, and Other Extractives

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Constituents of Alphitonia Species. III. Alphitexolide, a New Triterpene, and Other Extractives