Cyclopenta[b]benzofurans from Aglaia Species with Pronounced Antifungal Activity against Rice Blast Fungus (Pyricularia grisea)

Abstract

Eight flavaglines, six cyclopenta[b]benzofurans, a cyclopenta[bc]benzopyran, and a benzo[b]oxepine, together with an aromatic butyrolactone were isolated from Aglaia odorata, A. elaeagnoidea, and A. edulis (Meliaceae) and tested against the three plant pathogens Pyricularia grisea, Fusarium avenaceum, and Alternaria citri for antifungal properties. Using the microdilution technique linked with digital image analysis of germ tubes, the benzofurans displayed strong activity, whereas the benzopyran, benzoxepine, and butyrolactone were inactive at the highest concentration tested. P. grisea, responsible for rice blast disease, was the most susceptible fungus against all benzofurans, with rocaglaol as the most active derivative. Based on EC(50), EC(90), and MIC values, the antifungal activity of rocaglaol was clearly higher than of the reference compounds, blasticidin S and Benlate.

Terpenoid constituents and antifungal activity of Aglaia forbesii seed against phytopathogens

“…30 Antifungal activity of the other Aglaia spp. has been previously reported against a few organisms causing rice blast disease 12 and two other fungal plant pathogens in the genus Cladosporium. 8,10 With respect to the increasing negative effects of synthetic fungicides to humans and the environment, as well as the improved resistance of phytopathogenic fungi against conventional fungicides, our finding suggests possible benefits of bioactive compounds from A. forbesii seed for effective control of fungal plant pathogens.…”

“…1 Previous phytochemical investigations of plants in this genus have revealed the presence of a variety of compounds including several flavaglines (cyclopenta[b]benzofurans, cyclopenta[bc]benzopyrans, and benzo[b]oxepines), 2,3 bisamides, 4 triterpenoids (baccharane, cycloartane, dammarane, glabretal, lupane, and tirucallane types), 5 steroids (cholestane, ergostane, pregnane, and stigmastane types), 6,7 limonoids, 8 sesquiterpenes, 9 lignans, 10 and flavonoids. 11 Some of these known isolates were shown to possess high insecticidal activity, 4,11 antifungal activity, 12 antiviral activity, 13 anti-inflammatory activity, 14 as well as significant antiproliferative activity. 2 Aglaia forbesii, a large tree of up to 35 m, is widely distributed in the southern region of Thailand.…”

“…To date, only a few studies have been performed on the antifungal activities of some members of this genus, including A. elaeagnoidea, 8,12 A. leptantha, 10 A. edulis, 12 and A. odorata. 12 Our preliminary test for antifungal activity against the three plant pathogens Phytophthora botryosa, P. palmivora, and Rigidoporus microporus, based on the mycelium inhibition test, demonstrated that the ethanolic extract from the seed of this plant species exhibited more pronounced activity against phytopathogenic fungi tested than those from the leaves and pericarp, as well as some other medicinal plants previously documented for their good antibacterial activities in our laboratory, including Rhodomyrtus tomentosa and Quercus infectoria. 15 P. botryosa, P. palmivora, and R. microporus have been frequently isolated as the important phytopathogens in many economically important agricultural crops, especially rubber.…”

Synthesis and Isolation of Enantiomerically Enriched Cyclopenta[b]benzofurans Based on Products from Anodic Oxidation of 2,4‐Dimethylphenol

“…[3] Moreover, an insecticidal [1,4] and fungicidal activity was found. [5] The lead structure was devolved to commercially available synthetic prostacyclin agonist Beraprost ® which is a synthetic prostacyclin agonist which can be useful for a plethora of diseases like Alzheimer's disease or pulmonary hypertension. [6] Further examples for natural products based on the cyclopenta [b]benzofuran moiety are marine sesquiterpenes like aplysin.…”

Cytotoxic Studies on Two Meliaceae plants: Chukrasia Tabularis and Aglaia Roxburghiana

“…Benzofurans, unique structures of the genus aglaia, were shown to possess high insecticidal properties [3][4][5][6]. High fungicidal activity was also detected against the rice blast disease [7]. Furthermore, platelet aggregation inhibitory effects [8], antiviral [9], antibacterial [10] and anthelmintic bioactivities [11] were reported for this genus.…”