Vigna unguiculata is an important source of proteins and energy for humans and animals. However, postharvest losses caused by Callosobruchus maculatus can reach from 20 to 100% of stored seeds. In this study, the insecticide potential of compounds extracted from Himatanthus drasticus latex was assessed. The latex was extracted with ethanol (70%) and then partitioned through sequential use of hexane and chloroform. These fractions were investigated by chromatography to determine their chemical composition. Plumieride, identified in a hydroalcoholic subfraction, was tested for insecticidal activity against C. maculatus. The ethanolic fraction (LC 50 = 0.109; LC 90 = 0.106%) and the plumieride (LC 50 = 0.166; LC 90 = 0.167%) were lethal to larvae. Plumieride (0.25%) delayed larval development, and mortality reached 100%. Its inhibitory action on intestinal α-amylase from larvae was higher (89.12%) than that of acarbose (63.82%). Plumieride (0.1%) inhibited the enzyme α-amylase in vivo in the larval intestine. This result was confirmed by a zymogram test performed by SDS-PAGE when the enzyme electrophoresed on gel copolymerized with starch. When spread on seeds, the hydroalcoholic fraction (1.0%) reduced infestation. The loss of seed mass was 5.26% compared to the control (44.97%). The results confirm the effect of latex compounds in protecting stored seeds against weevil infestation.

BACKGROUND Calotropis procera latex protein fraction (LP) was previously shown to protect animals from septic shock. Further investigations showed that LP modulate nitric oxide and cytokines levels. OBJECTIVES To evaluate whether the protective effects of LP, against lethal bacterial infection, is observed in its subfractions (LP PII and LP PIII). METHODS Subfractions (5 and 10 mg/kg) were tested by i.p. administration, 24 h before challenging with lethal injection (i.p.) of Salmonella Typhimurium. LP PIII (5 mg/kg) which showed higher survival rate was assayed to evaluate bacterial clearance, histopathology, leukocyte recruitment, plasma coagulation time, cytokines and NO levels. FINDINGS LP PIII protected 70% of animals of death. The animals given LP PIII exhibited reduced bacterial load in blood and peritoneal fluid after 24 h compared to the control. LP PIII promoted macrophage infiltration in spleen and liver. LP PIII restored the coagulation time of infected animals, increased IL-10 and reduced NO in blood. MAIN CONCLUSIONS LP PIII recruited macrophages to the target organs of bacterial infection. This addressed inflammatory stimulus seems to reduce bacterial colonisation in spleen and liver, down regulate bacterial spread and contribute to avoid septic shock.

No abstract

Background: Calotropis procera is a laticiferous plant (Apocynaceae) found in tropical regions all over the world. The ultrastructural characteristics of laticifers, their restricted distribution among different taxonomic groups and in some species in each clade, as peptidases from latex, make them very attractive for biological analysis. Objective: To investigate the effects of LP-PII-IAA (laticifer protein (LP) sub-fraction II (PII) of C. procera presenting an iodoacetamide-inhibited cysteine proteinase activity) on irinotecan-induced intestinal mucositis, a serious adverse effect of this medicine for the treatment of cancer. Results: LP-PII-IAA is composed of closely related isoforms (90%) of peptidases deprived from catalysis and an osmotin protein (5%). Animals receiving co-administration of LP-PII-IAA presented a significant decrease in mortality, absence of diarrhea, histological preservation and normalization of intestinal functions. Clinical homeostasis was accompanied by a reduction in MPO activity and declined levels of IL-1β, IL-6 and KC while IL-10 level increased in LP-PII-IAA-treated animals. COX-2 and NF-kB immunostaining was reduced and the level of oxidative markers (GSH, MDA) were normalized in animals that received LP-PII-IAA. Conclusion: We suggest that peptidases from the latex of Calotropis procera were instrumental for the suppression of the adverse clinical and physiological effects of irinotecan.