Larvicidal activity,inhibition effect on development,histopathological alteration and morphological aberration induced by seaweed extracts in Aedes aegypti(Diptera:Culicidae)

Objective:To investigate the larvicidal activity,inhibition effect on development,histopathological alteration and morphological aberration induced by the extracts derived from seaweeds Bryopsis pennuta(B.pennata),Sargassum binderi(S.binderi) and Padina australis in Aedes aegypti(Ae.aegypti) larvae and to characterize the phytochetnical components of the three seaweeds.Methods:Larvicidal activity of the seaweeds towards the larvae of Ae.aegypti was determined according to WHO.The inhibition effect of seaweeds was assessed by determining the mortality,adult emergence rate,larval and pupa duration of the treated larvae.Histopathological effect on midgut epithelium of larvae and morphological aberration induced by the methanol extracts were examined.Phytochemical analysis was done to determine the presence of alkaloids,saponins,steroids and terpenoids in the seaweeds.Results:Chloroform partition of B.pennata extract exhibited the strongest larvicidal activity(LC_(50) = 82.55 μg/mL).followed by methanol extract of B.pennata(LC_(50) = 160.07 μg/mL) and chloroform partition of S.binderi extract(LC_(50) = 192.43 μg/mL).The methanol extract of S.bituleri exhibited the strongest effect on prolongation of larval period(1.5-fold longer as compared to control) and resulted in strongest inhibition effect in adult emergence(98.67%).The histopathological study showed that larvae treated with seaweed extracts had cytopathological alteration of the midgut epithelium.The morphological observation revealed that the anal papillae and terminal spiracles of larvae were the common sites of aberrations.Conclusions:The study provided information on various effects of seaweed extracts on Ae.aegypti.Further investigation on identifying the active compounds and their mechanisms of action is recommended.

Curculigo recurvata W.T.Aiton exhibits anti-nociceptive and anti-diarrheal effects in Albino mice and an in silico model

Background: Curculigo recurvata(C. recurvata) is an enthnomedicinally important herb reported to have significant medicinal values. The present study aimed to explore the in vivo and in silico anti-nociceptive and anti-diarrheal effects of a C. recurvate rhizome methanol extract(Me-RCR).Methods: The analgesic effects of Me-RCR were assessed using acetic acid-induced writhing and the formalin-induced flicking test. The drugs were administered intraperitoneally(IP) at doses of 200 and 400 mg/kg body weight(bw). Anti-diarrheal activity was evaluated by assessing intestinal motility, hypersecretion, and fecal score in mice at oral doses of 200 and 400 mg/kg·bw. Computer facilitated analyses for anti-nociceptive and anti-diarrheal activities of three isolated compounds from C. recurvata were undertaken to identify the best-fit phytoconstituents.Results: The Me-RCR showed significant(P <.05) peripheral anti-nociception at the highest dose. The extract inhibited both early and late phases of nociception in the formalin-induced writhing test. In the castor oil-induced diarrhoea model, the extract significantly(P <.05) prolonged the onset time of diarrhoea, inhibited percentage of diarrhoea, and decreased both the volume and weight of intestinal contents. Rates of intestinal fluid accumulation inhibition were(33.61 ± 1.00)% and(46.44 ± 0.89)% at Me-RCR doses of 200 and 400 mg/kg·bw, respectively. Moreover, a significant(P <.05) reduction in gastrointestinal motility was observed. An absorption, distribution, metabolism, excretion and/or toxicity(ADME/T) test showed that the selected compounds yielded promising results, satisfying Lipinski's rule of five for predicting drug-like potential. Notably, of the three phytoconstituents curculigine and isocurculigine possessed the highest affinity for the COX-1 and COX-2. Isocurculigine was also identified as the most effective anti-diarrheal compound in the computer-facilitated model.Conclusion: An extract of the plant C. recurvata showed potential analgesic and antidiarrheal activity due to the presence of one or more active secondary metabolite(s).

Bioactive compounds fractionated from endophyte Streptomyces SUK 08 with promising ex-vivo antimalarial activity

Objective: To determine ex vivo antimalarial activity and cytotoxicity of endophytic Streptomyces SUK 08 as well as the main core structure fractionated from its crude extract.Methods: The activities of SUK 08 crude extract were evaluated by using the Plasmodium lactate dehydrogenase assay and synchronization test against rodent malaria parasite Plasmodium berghei, instead of human malarial parasite Plasmodium falciparum. The cytotoxicity of the crude extract was determined by MTT assay. The crude extract was analyzed by thin-layer chromatography and gas chromatography–mass spectrophotometry.Results: The ethyl acetate crude extract showed very promising antimalarial activity with IC50 of 1.25 mg/m L. The synchronization tests showed that ethyl acetate extraction could inhibit all stages of the Plasmodium life cycle, but it was most effective at the Plasmodium ring stage. On the basis of a MTT assay on Chang Liver cells, ethyl acetate and ethanol demonstrated IC50 values of >1.0 mg/m L. The IC50 of parasitemia at 5% and30% for this extract was lower than chloroquine. Thin-layer chromatography, with 1: 9 ratio of ethyl acetate: hexane, was used to isolate several distinct compounds. Based on gas chromatography–mass spectrophotometry analysis, three core structures were identified as cyclohexane, butyl propyl ester, and 2,3-heptanedione. Structurally, these compounds were similar to currently available antimalarial drugs.Conclusions: The results suggest that compounds isolated from Streptomyces SUK 08 are viable antimalarial drug candidates that require further investigations.