Activity of Icacinol from Icacina trichantha on Seedling Growth of Oryza sativa and Arabidopsis thaliana

Abstract

Broadleaf weeds are very costly for crop growers. Additional herbicidal compounds need to be obtained, especially from natural sources. Extracts of Icacina trichantha were evaluated for responses in germinating seeds and seedlings of rice (Oryza sativa) and Arabidopsis (Arabidopsis thaliana). An ethyl acetate fraction of I. trichantha tuber and a diterpenoid constituent, icacinol (1), were found to have impacts on germination and growth of seedlings. The seed germination inhibitory activity on rice was minimal, but significant on Arabidopsis. While rice indicated some growth delay in leaf expansion in the presence of 1, the effects appeared temporary; chlorophyll and anthocyanins were not significantly altered compared to DMSO controls. Rice seedlings attained biomass similar to DMSO controls, and rice grains per panicle were not significantly different from the DMSO controls. On the other hand, Arabidopsis exhibited damage to leaf expansion, reduced chlorophyll, and increased anthocyanins in aerial portions of the seedlings. Icacinol (1) may be a suitable chemical agent to investigate further for the treatment of eudicot weeds.

Momilactone and Related Diterpenoids as Potential Agricultural Chemicals

“…Apart from the momilactones, icacinol ( 24 ) caused significant damages to Arabidopsis leaf expansion. 44 Arabidopsis plant treated with 24 also showed indications of stress, where anthocyanins increased and chlorophyll was reduced. Such findings reinforce the hypothesis that (9 β- H)-pimarane lactones may serve as a potential source of agrichemicals.…”

“…35 Phytochemical investigations of this plant in our laboratories have resulted in the isolation of 25 (9β-H)pimaranes and derivatives, including humirianthenolide C (11), 2β-hydroxyhumirianthenolide C (12), humirianthol (16), 14αmethoxyhumirianthol (18), icacinol (24), 17-hydroxyicacinol (25), icacenone (26), 7α-hydroxyicacenone (27), icacinlactones A−L (28, 30, 31, 34−42), 12-hydroxyicacinlactone A (29), 7αhydroxyicacinlactone B (32), 7β-hydroxyicacinlactone B (33), icacintrichanone (43), and icacintrichantholide (44). 29,36−39 The absolute configurations of 18, 27, 30, 31, 40, and 41 were established as (3S,4R,5R,6S,9S,10S,13S,14S,15S) (18), (2S,3R, 4R,5R,6S,7S,8S,9R) (27), (3S,4R,5R,6R,10R) (30), (2S,3R,4R, 5R,6R,10R) (31), and (3S,4R,5R,6R,8R,9R,10S) (40), (3S,4R, 5R,6R,10R) (41), and (3S,4R,5R,6R,10R) (44), respectively, by the single-crystal X-ray diffraction data. Compounds 28− 35, and 41−44 are proposed to be biosynthesized via a (9β-H)-pimarane pathway.…”

“…Dose-dependent responses were observed at 26.5 μM (66%), 53 μM (36%), and 265 μM (<1%). 44 3.2. Plant Growth Inhibition on Rice Field Weeds and Other Plants.…”

“…Our recent study revealed that icacinol ( 24 ) was able to reduce the germination of Arabidopsis seeds at 5.3 μM by 20%. Dose-dependent responses were observed at 26.5 μM (66%), 53 μM (36%), and 265 μM (<1%) …”

Phytotoxic ent-Isopimarane-Type Diterpenoids from Euphorbia hylonoma

“…Their phytotoxic effects on the growth of the roots and shoots of several different seedlings were tested. Previous studies showed that pimarane and ent -pimarane diterpenoids both exhibited significant phytotoxic activities. − However, few reports have examined the phytotoxic activities of ent -isopimarane diterpenoids. In the present study, some ent -isopimarane diterpenoids inhibited the growth of the roots and shoots of P. annua and Festuca arundinacea seedlings with inhibitory rates ranging from 50% to 84%.…”