No abstract

The ability to control soil-borne pathogens is mainly conditioned by the restrictions to the use of synthetic pesticides, and genetic resistance is hindered by new pathogen races or by only a partial expression of the resistance. Allelopathy, the antimicrobial activity of plant extracts, is a promising option against crop pathogens. Extracts from some Lycium spp. possess biological and therapeutic properties. Individual methanolic extracts from L. europaeum were each evaluated in vitro against Verticillium dahliae (Vd), Sclerotinia sclerotiorum (Ss) and Harpophora maydis (Hm). The mycelial growth of the three fungi was significantly reduced by all the extracts at doses of 10 and 30 µl mL-1. The sporulation of Hm was almost completely inhibited but that of Vd was stimulated by some of the extracts. Sclerotia of Ss were formed in a smaller number, their total weight increasing at high extract doses. In greenhouse, and as early as 6 weeks after inoculation, Hm caused significant decreases of weights in both roots and aboveground parts of maize. Decreased weights were also associated with the methanol aqueous solution control treatment. The detrimental effect of Hm on root weights was counteracted by one of the leaf extracts. Eleven phenolic compounds were separated in the extracts. The hydroxycinnamic acid family, including chlorogenic acid as a major compound, represented more than 50 % of the total content in all the samples. Rutin was the most abundant flavonoid. Bioactive L. europaeum extracts, after development into final products and combined with other tools, have the potential to protect crops in the field.

The antioxidant and hepatoprotective activities of hot aqueous extract from Asparagus albus (A. albus) leaf against CCl 4 -induced liver damage in rats were investigated. The total phenolic, flavonoid, and condensed tannin contents of hot aqueous extract from A. albus leaf were determined. The antioxidant activity of hot aqueous extract from A. albus leaf was evaluated using the antioxidant capacity, DPPH free radical-scavenging ability and reducing power assays. Different polyphenolic compounds, namely gallic acid, vanillic acid, 3,4 dimethoxybenzoic acid, catechin, rutin, and quercetin were identified. Oral administration of hot aqueous extract from A. albus leaf to male Wistar, intoxicated with CCl 4 , demonstrated a significant protective effect by lowering the levels of hepatic marker enzymes (aspartate and lactate transaminases) and by improving the histological architecture of the rat liver. The hot aqueous extract from A. albus leaf attenuated oxidative stress by restoring the activities of superoxide dismutase, catalase, and glutathione peroxidase.This study demonstrated that the hot aqueous extract from A. albus leaf protects rat liver from CCl 4 -induced injury and suggests a potential therapeutic use for A. albus plant. Practical applicationsThe hepatoprotective effects of plant extracts are mainly related to their richness in phenolic compounds. Phenolic compounds are secondary metabolites widely found in plants, mostly represented by phenolic acids and flavonoids. The growing interest in these bioactive antioxidant components is principally due to their antioxidant potential and the association between their consumption and the prevention of some diseases. In this study, a remarkable hepatoprotective effect of the hot aqueous leaf extract obtained from Asparagus albus was detected against CCl 4 -induced liver injury in rat and its mechanism was related, at least in part, to its free radical scavenging and antioxidant activity on account of the presence of polyphenols.

The purpose of the present investigation is to assess, for the first time, the antidiabetic, antihyperlipidemic and antioxidant activities of Lycium europaeum extract in alloxan-induced diabetic rats. Diabetes was induced in adult male Wistar rats via a single subcutaneous alloxan injection (120 mg/kg). Lycium europaeum aqueous extract was orally administered at a dose of 20 mg/kg for 28 consecutive days. Serum concentrations of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglycerides (TG) were assayed at the end of the experimental period in all investigated groups. Antioxidant enzymes such as glutathione peroxidase (GPx), catalase (CAT) and superoxide dismutase (SOD) were sought in the serum and pancreas. Lycium europaeum extract significantly increased HDL-C and reduced blood glucose, TC, LDL-C and TG as compared to the alloxan-control group. Lycium europaeum extract was also efficient in reducing oxidative stress in diabetic rats by increasing SOD, CAT and GPx activities both in the pancreas and the plasma of the animals. Moreover, Lycium europaeum extract contained considerable levels of polyphenols and flavonoids. It also exhibited an important antioxidant capacity and a remarkable ability to quench DPPH radicals and reduce irons. The obtained results highlight potentially relevant health beneficial effects of Lycium europaeum extract, reversing hyperglycemic, hyperlipidemic and oxidative stress effects in rats with alloxan-induced diabetes. Therefore, it may be considered as a promising alternative or complementary agent to diabetes treatment.