Identification of autotoxic compounds from fibrous roots of Panax quinquefolium L.

Abstract

Panax quinquefolium (American ginseng) is a perennial understory herb that has been widely used as a medicinal plant in China and other countries. Autotoxicity has been reported to be one of the major problems hindering the consecutive cultivation of American ginseng. However, the potential autotoxic compounds produced by the root of American ginseng are less well known. Here, we report the isolation and characterization of five groups of autotoxic compounds from aqueous extracts of the fibrous roots of American ginseng. Ether extracts of the water-soluble compounds were further analyzed and separated into seven fractions. Among them, the most autotoxic fraction (Fraction V) was subjected to GC/MS analysis, and 44 compounds were identified. Based on literature information, 14 individual compounds were selected and their autotoxic effects on seedling growth were further tested. The results revealed that, of these 14 compounds, 9 phenolic compounds significantly reduced the growth of seedlings in a concentration-dependent manner, while 5 aliphatic compounds showed modest inhibition at all three concentrations tested. Furthermore, we verified the existence of the autotoxic compounds in the plow layer soil of commercially cultivated American ginseng fields, and the concentration of these compounds as determined by HPLC analysis was in line with the concentration determined to be bioactive. Taken together, our study established a functional link between the compounds produced by American ginseng and their autotoxic effects.

AUTOTOXICITY IN TOUGH LOVEGRASS ( Eragrostis plana )

“…Autototoxicity is an important phenomenon in controlling population density in natural systems (He et al ., 2009). In tough lovegrass, it is a mechanism that possibly is involved in controlling the germination and growth of plants of the species itself, which could explain the gaps between their tussocks in the field .…”

In vitro study of the growth, development and pathogenicity responses of Fusarium oxysporum to phthalic acid, an autotoxin from Lanzhou lily

“…By applying natural blends of phytochemicals derived from root exudates of Arabidopsis to the soil, Badri et al (2013) found that phenolic-related compounds predominantly modulate the soil microbiome. Increasingly, studies have shown that particular autotoxins (phenolicrelated compounds) from root exudates not only directly suppress the growth of the plant itself (Asao et al 2007;He et al 2009;Kong et al 2008;Li et al 2012;Mahall and Pramanik et al 2001;Yu et al 2000), but also indirectly stimulate soil-borne pathogens, and thus enhance disease incidences (Manici et al 2004;Nicol et al 2003;Ye et al 2004;Zhang et al 2010). Autotoxins might influence the progression of soil-borne pathogens by modulating the resistance system of plants to pathogen infection (Nigh 1989).…”

Effect of Intercropping of Angelica sinensis with Garlic on its Growth and Rhizosphere Microflora

“…Soil sickness is usually found in agricultural crops, especially in medicinal plant (Zhang et al, 2005;He et al, 2009;Yin et al, 2009). Soil sickness may be attributed to autotoxicity, soil microflora imbalance and changes in soil physiochemical properties (Young, 1984;Yu and Matsui, 1994).…”