L-3,4-dihydroxyphenylalanine as an allelochemical candidate from Mucuna pruriens (L). DC. var. utilis.

Abstract

Velvetbean(Mucuna pruriens (L.) DC. var. utilis oi Stizolobium deeringianum Piper et Tracy, synonymbut now not recommended)1>2) is a tropical legume, cultivated as green manureor as a cover crop. Velvetbean leaves are used as fodder, the seeds as food, and the seeds and stems as medicine in Africa and China.3) The yield of seeds reaches 1.5-2t/ha, and offresh leaves and stems comestc 20-30t/ha, this crop being one of the most productive ir the world.Mucuna pruriens has been reported to increase the graminaceous crop yield in mixed culture, but to smother notorious weeds such as nutsedge (Cyperus spp.) and alang-alang (Imperata cylindrica).4) We have screened allelopathic plants with seedling growth tests, and evaluated velvetbean as the most promising candidate.5 Field tests showed the least weed population in velvetbean stands in contrast to the stands of other crops and fallow conditions.6) A dwarf species of velvetbean, cv. ana (a cultivar in Brazil), was used. For the bioassay,5) ten lettuce seeds were placed in 4.5cm diameter Petri dishes containing 1.0ml oi the test solution on Whatman No. 1 filter papers, and were incubated at 25°C in the dark. The germinated seeds were counted and the hypocotyl and radicle growth was measuredon the 4th day. Fresh fully expanded leaves and roots of velvetbean were extracted with 80%etha-nol. The acid fraction of the extract inhibited the growth of lettuce seedlings. This fraction was subjected tc silica gel column chromatography (from 100% benzene tc 100% ethylacetate with a 5% step up, then to 100% methanol with a 5% step up, the active fraction being ethylacetate-benzene (50 : 50)), and HPLC with an ODS column (concave gradient from 1 5% methanol in 2% acetic acid to 99% methanol in 2% acetic acid), and the major inhibitor was identical to L-3,4-dihydroxyphenylalanine

Allelopathic activities of selected Mucuna pruriens on the germination and initial growth of lettuce

“…These observations correspond to work by Fujii et al [19] which reported that mucuna had no effect on seed germination when lettuce seeds were treated with mucuna leaves, stem, and root extracts. However, morphological observation of lettuce radicle in the plant-box showed that lettuce seedlings in and around the root-zone separating tube had some discoloration.…”

“…The crude extract of fresh leaves and stems of hairy vetch (Vicia villosa) showed inhibitory activity on hypocotyl and radicle elongation of lettuce to a level of 50% [18]. Continuous cropping of mucuna on the field reduced weeds to about half of the fallow plots and one quarter of the plots with other crops such as upland rice, eggplant, and tomato [19]. Fujii et al, [20] reported L-3, 4-Dihydroxyphenylalanine (L-DOPA) as the allelochemical in mucuna inhibiting plant growth.…”

Bioactive potential of the wild mushroom Astraeus hygrometricus in South-west India

“…The L-3,4-Dihydroxyphenylalanine (L-DOPA) of mushroom samples was determined based on the method by Fujii et al (1991). Samples of mushroom flour was mixed with distilled water (1 ml) followed by incubation at room temperature (2 h), centrifuged (1500 rpm) and supernatant was concentrated to dryness using rotary evaporator.…”

AFLP assessment of genetic diversity among Indian Mucuna accessions

“…Reported to be native of China and Eastern India (Wilmot Dear 1987)-the plant is now distributed in several parts of the World with newer production niches. In addition to 20-30 % protein content (Bressani et al 2003), it produces seed yield of 2,000 kg/hectare (Buckles 1995); performs well under dry farming and low soil fertility conditions (Siddhuraju et al 2000); shows resistance against wide ranging diseases (Eilitta et al 2002); exhibits allelopathic properties (Fujii et al 1991) and is effective in lowering nematode population (Carsky and Ndikawa 1998;Queneherve and Martiny 1998).…”