Crude extracts (methanol) of various parts, viz. the leaves, fruits, roots, stem and trunk bark, of Garcinia atroviridis were screened for antimicrobial, cytotoxic, brine shrimp toxic, antitumour-promoting and antioxidant activities. The crude extracts exhibited predominantly antibacterial activity with the root extract showing the strongest inhibition against the test bacteria at a minimum inhibitory dose (MID) of 15.6 microg/disc. Although all the extracts failed to inhibit the growth of most of the test fungi, significant antifungal activity against Cladosporium herbarum was exhibited by most notably the fruit (MID: 100 microg), and the leaf (MID: 400 microg) extracts. None of the extracts were significantly cytotoxic, and lethal towards brine shrimps. The root, leaf, trunk and stem bark extracts (except for the fruits) showed strong antioxidant activity exceeding that of the standard antioxidant, alpha-tocopherol. Antitumour-promoting activity (>95% inhibition) was shown by the fruit, leaf, stem and trunk bark extracts.

Ethanol extracts of 19 Malaysian traditional vegetables (locally known as 'ulam')

No abstract

In order to develop an effective trunk-injection agent against pine wood nematode, Bursaphelenchus xylophilus, an in vitro assay was used to examine the antinematodal activity of 58 commercially available compounds with known modes of action. Among compounds tested, the GABA receptor agonists had better anti-nematodal activity than compounds in¯uencing glutamate, Nmethyl-D-aspartate, b-adrenergic, dopamine, muscarinic acetylcholine and nicotinic acetylcholine receptors, as well as those inhibiting acetylcholinesterase, monoamine oxidase, 5-hydroxytryptamine uptake and Ca 2 , K , Na and Cl À channels. Avermectins and milbemycins strongly inhibited propagation of the nematode. Emamectin benzoate proved to be the most active (IC 95 0.050 mM) being over 140 times more active than the active ingredient of conventional trunk-injection agents. It is concluded that emamectin benzoate is a strong candidate for an anti-nematodal trunk injection agent.

Two novel oxazolomycin isomers, oxazolomycins B (2) and C (3), were isolated from the fermentation broth of an oxazolomycin-producing strain, Streptomyces albus JA3453. Both compounds are geometrical isomers of oxazolomycin (1), the configurations of their triene moieties being (4'E, 6'E, 8'E) (2) and (4'Z, 6'E, 8'E) (3) while that of oxazolomycin (1) is (4'Z, 6'Z, 8'E). Compounds 2 and 3 exhibited potent inhibitory activity against crown gall formation with the same MIC (0.8 microgram/disk) as oxazolomycin. Compounds 2 and 3 showed no antibacterial activity against Agrobacterium tumefaciens, in contrast to oxazolomycin which has specific anti-A. tumefaciens activity.