Antifeedant Research Articles

Controlling Properties of the Hydroalcohol-glycol Extract of Plant Species, Myrtaceae Family, on Callosobruchus Maculatus in Grass Legume.

Some plants of the Myrtaceae family have active principles that inhibit the development and growth of many insects, according to experts, with antifeedant effect, repellent and insecticide. In the present study, we evaluated the bioactivity of three doses of compound extract from seeds of Myrciaria dubia (Kunth) McVaugh, Myrtaceae, bioprocessed in order to use them for the biocontrol of Callosobruchus maculatus in the grass legume Vigna unguiculata (L.) Walp (cowpea) without previous treatment. The sequential probability ratio test for the period and minimum dose of extract application was applied with and without the presence of M. dubia, inter-related to the health and physiological behavior of cowpea, evaluated initially at six and fifty days of infestation. The positive effect was obtained around 94% for the health and in the physiological evaluation, an average value of 73% of effectiveness on the doses tested, which showed no significant difference with each other. The extract caused the death of adult C. maculatus and the immobilization of hatchings in cowpea. In the In vitro conditions, it has insecticidal and controlling bioactive properties with potential for use in preservation of stored seeds and grain of grass legumes such as Vigna unguiculata (L.) Walp.

Insecticidal properties of Citrus hystrix DC leaves essential oil against Spodoptera litura fabricius

Chemical analyisis by GC and GC-MS revealed presence of 29 compounds in the essential oil fraction of kaffir lime, Citrus hystrix fresh leaves. Beta-citronellal was the major compound present with 66.85% of total oil followed by beta-citronellol (6.59%), linalool (3.90%) and citronellol (1.76%). Insecticidal properties of C. hystrix leaves essential oil was investigated against tobacco army worm, Spodoptera litura using topical application bioassay on uniform weighted second instar larvae in the laboratory. Essential oil was effectively in killing the larvae and showed that the LD50 is 26.748 µL/g. Insect development and growth index observations showed that the essential oil had antifeedant properties resulting in severe growth inhibition of S. litura. Key words: Citrus hystrix, Spodoptera litura, essential oil, botanical insecticides.

Potential of Mammea siamensis as a botanical insecticide: Its efficiency on diamondback moth and side effects on non-target organisms

Nine species of local Thai medicinal plant extracts with known insecticidal properties that is,Acorus calamus, Eugenia caryophyllus, Mammea siamensis and 6 species of Stemona(Stemona curtisii, Stemona tuberosa, Stemona burkillii, Stemona kerrii, Stemona unknown 1 and Stemona unknown 2) were screened for the highest insecticidal activity by the brine shrimp lethality test (BST). M. siamensis showed a very strong toxic effect on brine shrimp with the lowest 24 h LC50 value of 0.072 µgml-1. The purification of its active compound was conducted using chromatographic methods and the BST to select the most effective fraction. The spectroscopic methods were used for the identification of the active compound. Surangin B was finally identified as the active compound. Its insecticidal effectiveness on the 3rd instar larvae of diamondback moth was investigated by topical application and leaf dipping methods in comparison with methomyl. The results indicated that surangin B demonstrated high in both contact and anti-feedant activities than methomyl. According to its side effects on non-target organisms, M. siamensis exhibited no negative impact on earthworm and honeybee. In contrast, it showed a higher toxicity on fish than methomyl. From the results it can be concluded, that M. siamensis might be one of the natural insecticides for the diamondback moth management. Key words: Plutella xylostella Linn., botanical insecticide, surangin B, bioactive compound.

Antifeedant and antimicrobial activity of Tylophora indica

Crude and pure extracts of Tylophora indica were investigated in view of antifeedant, antibacterial and antifungal properties. Leaf crude extract showed more antifeedant activity than stem and root against Spodoptera litura, a polyphagous pest on wide ranging crops. Among the pure compounds isolated, Tylophorine showed the highest antifeedant activity followed by Septicine, O-Methyl Tylophorinidine and simple aliphatic acid. Similarly the crude extracts of leaf has exhibited higher antibacterial activity than root and shoot against Basillus subtilis, Staphylococcus aureus, Mycrococcus luteus and P. aergenosa. In contrast, Escherichia coli was not inhibited even at higher concentrations of either crude extracts or extracted pure compounds of T. Indica. Pure compounds displayed strong antibacterial activity at lower concentrations in all tested bacterial strains except E. coli. While all the crude and pure compounds showed antifungal activity against Aspergillus niger, Aspergillus fumigatus and Trichoderma viridae, the pure compounds had strong antifungal activity compared to crude extracts. Key words: Tylophora indica, antifeedant activity, antimicrobial activity.

Cucurbitane-type triterpenoids in Momordica charantia Linn.

Momordica charantia Linn, belonging to the family of Cucurbitaceae, is a useful medicinal and vegetable plant for human health and one of the most promising plants for diabetes. Cucurbitane-type triterpenoidsare the main active constituents of M. charantia and have a number of potential biological and pharmacological activities including antidiabetic, anti-obesity, anticancer, anti-HIV, antifeedant and antioviposition activities. Since the early 1960’s the constituents of bitter melon have been investigated and several classes of secondary metabolites including cucurbitane-type triterpenoids have been isolated. Charantin, an anti-diabetic compound, is a typical cucurbitane-type triterpenoid in M. charantia and is a potential and promising substance for the treatment of diabetes. This review summarized previous and current information regarding cucurbitane-type triterpenoids in M. charantia and provides new insights into its underlying chemical isolation and activities. Key words: Biological and pharmacological activities, charantin, cucurbitane-type triterpenoids, diabetes, Momordica charantia Linn.