Antimicrobial and pesticidal activity of partially purified flavonoids of Annona squamosa

Phytochemical constituents, bioactivities, and applications of custard apple (Annona squamosa L.): A narrative review

Annona squamosa L. (Annonaceae) is a versatile tree with an edible fruit showing abundant medicinal and industrial applications. The nutritional values of this plant are due to carbohydrates, proteins, amino acids, and vitamins. Ethnopharmacological uses referred to treatment of dysentery, headlice, cancer sores, purgative, and tonic effects. The main reported biological activities for A. squamosa L. were cytotoxic, antidiabetic, antimicrobial, antiparasitic, antioxidant, antimalarial, molluscidal, anthelmintic and insecticidal activities, and its chemical classes encompassed alkaloids, diterpenes, acetogenins, and cyclopeptides. The nutritional content of A. squamosa L. and their main chemical components, biological effects, and the different applications were discussed in this review. This comprehensive review strived to compile all the relevant data in the period between 1990 and 2023 covering databases PubMed, ScienceDirect, Web of Science, Googlescholar and Reaxys concerning A. squamosa L. different parts with their reported phytochemical constituents and biological activities to integrate a better understanding of the medicinal values.

Combining transcriptome and metabolome analysis to understand the response of sorghum to Melanaphis sacchari

BACKGROUND

The sorghum aphid Melanaphis sacchari (Zehntner) (Homoptera: Aphididae) is an important insect in the late growth phase of sorghum (Sorghum bicolor L.). However, the mechanisms of sorghum response to aphid infestation are unclear.

RESULTS

In this paper, the mechanisms of aphid resistance in different types of sorghum varieties were revealed by studying the epidermal cell structure and performing a transcriptome and metabolome association analysis of aphid-resistant and aphid-susceptible varieties. The epidermal cell results showed that the resistance of sorghum to aphids was positively correlated with epidermal cell regularity and negatively correlated with the intercellular space and leaf thickness. Transcriptome and metabolomic analyses showed that differentially expressed genes in the resistant variety HN16 and susceptible variety BTX623 were mainly enriched in the flavonoid biosynthesis pathway and differentially expressed metabolites were mainly related to isoflavonoid biosynthesis and flavonoid biosynthesis. The q-PCR results of key genes were consistent with the transcriptome expression results. Meanwhile, the metabolome test results showed that after aphidinfestation, naringenin and genistein were significantly upregulated in the aphid-resistant variety HN16 and aphid-susceptible variety BTX623 while luteolin was only significantly upregulated in BTX623. These results show that naringenin, genistein, and luteolin play important roles in plant resistance to aphid infestation. The results of exogenous spraying tests showed that a 1‰ concentration of naringenin and genistein is optimal for improving sorghum resistance to aphid feeding.

CONCLUSIONS

In summary, the physical properties of the sorghum leaf structure related to aphid resistance were studied to provide a reference for the breeding of aphid-resistant varieties. The flavonoid biosynthesis pathway plays an important role in the response of sorghum aphids and represents an important basis for the biological control of these pests. The results of the spraying experiment provide insights for developing anti-aphid substances in the future.

Larvicidal property and active compound profiling of Annona squamosa leaf extracts against two species of diptera, Aedes aegypti and Anopheles stephensi

Background & objectives

Vector control measures are important in lowering the spread of infections spread by mosquito. Synthetic pesticides used to suppress vector populations during the larval stage have had adverse impacts on people and the environment. The early III instar larvae of Aedes aegypti and Anopheles stephensi were the targets of the current experiment, which assessed the larvicidal ability of petroleum ether, chloroform, methanol, and aqueous extracts of Annona squamosa leaves.

Methods

Using the standard World Health Organization (WHO) larval bioassay test, leaf extracts were evaluated for their activity against Ae. aegypti and An. stephensi to determine lethal doses. Phytochemical analysis and gas chromatography-mass spectrometry (GC-MS) were carried out to identify larvicidal components in the extract. Further analysis using a scanning electron microscope (SEM) was done to check the extracts toxicity for both mosquito larvae.

Results

The larvicidal active components were identified by GC-MS as tetradecanoic acid, cis-vaccenic acid, and 2,4-di-tert-butylphenol etc. Methanol leaf extracts of A. squamosa (ASME) exhibited strong larvicidal activity against the early 3rd instar larvae of Ae. aegypti and An. stephensi with Lethal concentration (LC50) values of 51.450 ppm and 107.121 ppm. Cell damages to the larva post exposure to ASME were examined.

Interpretation & conclusion

This finding showed that the ASME has better larvicidal activity and its components that may be used to kill larvae as larvicides. The extracts toxicity towards damage of midgut of larva further suggests that this plant methanol leaf extracts could be effective in larval growth control approaches.

In Vitro Effect on Plasmodium falciparum and In Vivo Effect on Plasmodium berghei of Annomaal, an Oily Fraction Obtained from the Seeds of Annona squamosa

Malaria remains a life-threatening health problem and is responsible for the high rates of mortality and morbidity in the tropical and subtropical regions of the world. The increasing threat of drug resistance to available artemisinin-based therapy warrants an urgent need to develop new antimalarial drugs that are safer, more effective, and have a novel mode of action. Natural plants are an excellent source of inspiration in searching for a new antimalarial agent. This research reports a systematic investigation for determining the antimalarial potential of the seeds of A. squamosa. The study shows that the crude seed extract (CSE), protein, saponin, and the oily fractions of the seeds were nontoxic at a 2000 mg/kg body weight dose when tested in Wistar rats, thus revealing high safety is classified as class 5. The oily fraction, Annomaal, demonstrated pronounced antimalarial activity with low IC₅₀ (1.25 ± 0.183 μg/mL) against P. falciparum in vitro. The CSE and Annomaal significantly inhibited the growth of P. berghei parasites in vivo with 58.47% and 61.11% chemo suppression, respectively, while the standard drug artemether showed chemo suppression of 66.75%. Furthermore, the study demonstrated that oral administration of Annomaal at a daily dose of 250 mg/kg/day for 3 days was adequate to provide a complete cure to the P. berghei-infected mice. Annomaal thus holds promise as being patient-compliant due to the shorter treatment schedule, eliminating the need for frequent dosing for extended time periods as required by several synthetic antimalarial drugs. Further studies are needed to determine the active compounds in the oily fraction responsible for antimalarial activity.

Pharmacological assessment of the heartwood of Acacia raddiana Willd for antifungal potential

As COVID-19 suppresses the immune system and those who have recovered from COVID-19 are at risk of developing mucormycosis or black fungus so there is a need to develop new antifungal strategies by the use of medicinal plants. Medicinal plants have always been a subject of interest for drug discovery, ethno-botany, traditional and indigenous medicines. One of the successful strategies for the investigation of new bioactive compounds from medicinal plants includes the screening of plant extract, fractions followed by the purification of the constituents and screening for biological activity. In the present study, the heartwood of desert plant Acacia raddiana Willd was screened for antifungal activity by Agar-well diffusion method against Aspergillus flavus, Aspergillus niger, Candida albicans, Penicillium chrysogenum and Trichophyton rubrum. The result obtained shows that heartwood extract and their fractions serve as an effective agent against selected fungi and efficiency is dependent upon the nature of fraction and vary with respect to specific fungi. The extract and fractions shows a wide antifungal potential against C. albicans. The findings suggest that the medicinal plant under investigation might be a reasonable solution for fungal infections especially against C. albicans.

Global Trends of Green Pesticide Research from 1994 to 2019: A Bibliometric Analysis

The fast-growing world population places food production under enormous pressure to ensure food security. One of the most common methods to increase food production is the use of pesticides, but the continuous use thereof has numerous detrimental effects on the environment. The interest in biopesticides for a possible substitute has grown over the past two decades. To determine the research evolution of biopesticides (green pesticides), a bibliometric analysis from 1994 to 2019 was carried out. A total of 580 documents were found eligible in the Scopus database for this analysis. Parameters such as the number of articles, article citations, keywords, source impact, and countries of publication were used to analyse the documents and rank countries based on authors, productivity, article citations, and co-authorship. The analysis reveals production increased significantly from 2009 and has the most published documents in 2019 with a total of 74 articles. Asia's most populous countries, India and China, were ranked first and second, respectively, and the USA third in terms of the most productive countries in the field of plant biopesticides. Countries in Europe and Africa however have fewer publications than expected in this field, given the fact that they are high consumers of pesticides. India, China, and the USA have 4.08%, 2.94%, and 12.5% multiple country publications (MCPs), respectively, with the USA having a stronger collaboration. Finally, there is a clear indication in this study that India and China are taking the lead in substituting synthetic pesticides with the alternative natural plant biopesticide.

GC-MS profiling and assessment of antioxidant, antibacterial, and anticancer properties of extracts of Annona squamosa L. leaves

Background

The research and application of plants in food supplements and drugs have attracted great interest. This study aimed to examine the efficiency of several solvents for the extraction of the main compounds from Annona squamosa leaves and to evaluate the antioxidant, antibacterial, and anticancer activities of these extracts.

Methods

Gas chromatography-mass spectrometry was used to screen the bioactive compounds of A. squamosa methanolic extract. The free radical, hydrogen peroxide, and nitric oxide scavenging activities of the extracts were investigated. Furthermore, MTT, nuclear staining, LDH, and monolayer wound repair assays were performed to evaluate the potential anticancer activity of the extracts in colon cancer cells while the antibacterial activity was tested by using a well diffusion assay.

Results

A. squamosa leaves extracts were found to contain several bioactive compounds, of which the majority were sesquiterpenes (C₁₅H₂₄). These extracts exhibited strong antioxidant activity and antibacterial potency against both gram-positive and gram-negative bacteria. Different A. squamosa leaves extracts displayed remarkable antiproliferative, cytotoxic, antimigration, and apoptotic activities in colon cancer cells.

Conclusions

A. squamosa leaves contain major bioactive compounds that inhibit the growth of several types of bacteria and colon cancer cell lines, which demonstrated their efficacy as an alternative source of antibiotics and for the development of novel drugs for colon cancer therapy.

Toxicities of acetogenin-based bioacaricides against two-spotted spider mite and selectivity to its phytoseiid predators

Tetranychus urticae is the main pest of strawberry crops and can cause up to 80% of productivity losses under high infestations. Aiming to search T. urticae management alternatives compatible with eco-friendly or organic-based food production systems, this study evaluated the lethal and sublethal toxicities of formulated derivatives from Annonaceae (rich in acetogenins) against this pest species. In addition, it also evaluated the selectivity of the most promising formulation to the predatory mites Neoseiulus californicus and Phytoseiulus macropilis, which are largely applied in biological control in Brazil. Among the derivatives tested, the emulsion from the ethanolic seed extract of Annona mucosa-ESEAm (major component: acetogenin bis-tetrahydrofuran rolliniastatin-1) caused pronounced mortality of T. urticae after 120 h of exposure (LC₅₀ = 465.5 mg L^-1), in a comparable or superior manner to an abamectin-based synthetic acaricide used as positive control (LC₅₀ = 1243.4 mg L^-1). Moreover, ESEAm exposure resulted in a significant decrease in the number of eggs laid by females and caused the most pronounced ovicidal action for T. urticae, with only 5% embryonic viability. However, ESEAm also showed high toxicity to the predatory mites tested, causing 100% mortality for both species after 120 h exposure, similar to abamectin. The interaction between these bioacaricides and biological control agents should be tested under field conditions to further assess the potential ecological selectivity of these derivatives.

Flavonoid epimers from custard apple leaves, a rapid screening and separation by HSCCC and their antioxidant and hypoglycaemic activities evaluation

Leaves of custard apple are widely used in many places as a popular dietary supplement for the treatment of diabetes. Flavonoids are known to have anti-diabetic activity. In this study, the main flavonoid epimers were separated. The crude extract was first screened by HPLC-DAD before and after incubation with DPPH method to evaluate the antioxidants. An efficient extraction method was employed to remove non-flavonoid components. Subsequently, five main flavonoids with two pairs of epimers including quercetin-3-O-robinobioside, rutin, quercetin-3-O-β-D-glucoside, kaempferol-3-O-robinobioside, and kaempferol-3-O-rutinoside were successfully separated by high-speed counter-current chromatography with ethyl acetate/n-butanol/water (4:1:5, v/v) coupled with online-storage inner-recycling mode. The structures of the separated compounds were identified by spectral techniques. The purity of the separated flavonoid glycosides was over 98%, as determined by HPLC. The separated pure constituents were found to possess the antioxidant capacities following DPPH radical scavenging protocol. The compounds (1-3) exhibited better antioxidant activity. Furthermore, the glucose uptake of crude flavonoid extract had better results than the crude ethanol extract. The present study demonstrates that the efficacy of custard apple leaves in lowering glucose level, and antioxidant capacities of separated pure compounds probably appear to be predominantly responsible for hypoglycaemic properties on HepG2 cells.

Toxic Keratitis After Application of Custard Apple Seed for Head Lice Infestation

PURPOSE

To report the clinical features and outcomes of toxic keratitis after application of powdered custard apple seeds for hair washing for head lice infestation.

METHODS

Retrospective review of all patients with toxic keratitis after application of powdered custard apple seed for head lice infestation during the time period from January 2015 to December 2017. Demographic details, clinical features, and visual outcomes were documented.

RESULTS

Thirty-one eyes of 19 patients with toxic keratitis after application of crushed custard apple seeds for head lice infestation were included in the study. Eighteen females and 1 male with a median age of 14 years [interquartile range (IQR) 12-34 years] presented with severe epiphora, congestion, photophobia, and defective vision (median logMar visual acuity 0.4, IQR 0.2-0.8) after application of custard apple seed powder for hair washing. Ten eyes (32.2%) had an epithelial defect (median size 9 mm, IQR 5-12 mm), and 21 (67.7%) eyes had punctate epithelial erosions. All the patients were treated with topical antibiotics, and at 3 days follow-up, all of them had resolution of symptoms and signs with a median logarithm of the minimum angle of resolution (logMAR) visual acuity of 0 (IQR 0-0.2).

CONCLUSIONS

Health education about the harmful effect of this traditional practice for head lice infestation will prevent further similar events.

Plant-Derived Substances Used Against Beetles-Pests of Stored Crops and Food-and Their Mode of Action: A Review

Plants are sources of numerous active substances that are used to protect crops. Currently, due to the limitations of using synthetic insecticides, plant products have attracted increasing attention as possible pesticides. In this review, we discuss some of the most interesting plant products (for example, Solanaceae, or Asteraceae extracts, Artemisia absinthium or Citrus spp. essential oils, and single compounds like α-chaconine, or α-solanine) that exhibit insecticidal activity against beetles that are pests of stored food products. Next, we describe and discuss the mode of action of these products, including lethal and sublethal effects, such as antifeedant or neurotoxic activity, ultrastructural malformation, and effects on prooxidant/antioxidant balance. Furthermore, the methods of application of plant-derived substances in food storage areas are presented.

A Review on Annona squamosa L.: Phytochemicals and Biological Activities

Annona squamosa L. (Annonaceae) is a fruit tree with a long history of traditional uses. A. squamosa is an evergreen plant mainly located in tropical and subtropical regions. Srikayas, the fruits of A. squamosa, are extensively used to prepare candies, ice creams and beverages. A wide range of ethno-medicinal uses has been related to different portions of A. squamosa, such as tonic, apophlegmatisant, cool medicine, abortient and heart sedative. Numerous research projects on A. squamosa have found that it has anticancer, anti-oxidant, antidiabetic, antihypertensive, hepatoprotective, antiparasitic, antimalarial, insecticidal, microbicidel and molluscicidal activities. Phytochemistry investigations on A. squamosa have considered annonaceous acetogenins (ACGs), diterpenes (DITs), alkaloids (ALKs) and cyclopeptides (CPs) as the main constituents. Until 2016, 33 DITs, 19 ALKs, 88 ACGs and 13 CPs from this species were reported. On the basis of the multiple researches on A. squamosa, this review strives to integrate available information on its phytochemicals, folklore uses and bioactivities, hoping to promote a better understanding of its medicinal values.

A Standardized Composition Comprised of Extracts from Rosmarinus officinalis, Annona squamosa and Zanthoxylum clava-herculis for Cellulite

Background

Cellulite, characterized by changes in the skin morphology presented as dimpled or puckered skin appearance, is highly prevalent among postadolescent women. Cellulite management ranges from topical cream applications to invasive procedures. While some interventions showed improvements in physical appearances of affected areas, so far, none have reversed the condition to a full recovery. These unsuccessful measures signify the intricate nature of cellulite etiology highlighting its complexity leading to the possibility for a combination treatment approach to target multiple mechanisms.

Materials and Methods

We screened our plant library for extracts that reduce cellular lipid accumulation, improve microcirculation, possess high total antioxidant capacity, significant anti-platelet aggregation, and anti-inflammatory activities using lipid accumulation assay in 3T3-L1 cells, Croton oil-induced hemorrhoid test in rats as a model for microcirculation, anti-platelet aggregation assay, nitric oxide (NO) inhibition assay, and 1,1-diphenyl-2-picrylhydrazyl assay.

Results

Three known botanicals such as Rosemary officinalis, Annona squamosa and Zanthoxylum clava-herculis were identified as lead extracts in these tests. Treatment of 3T3 cell with A. squamosa at 1 μg/ml resulted in 68.8% reduction in lipid accumulation. In croton oil-induced hemorrhoid study, Z. clava-herculis reduced the recto-anus coefficient by 79.6% at 6 mg/kg indicating improvement in microcirculations. Similarly, R. officinalis caused inhibition of 82%, 71.8%, and 91.8% in platelet aggregation, NO production and free radical generation at 31.25 μg/ml, 6.2 μg/ml, and 40 μg/ml concentrations suggesting its anti-oxidant, and anti-inflammatory activities.

Conclusions

Data depicted here suggest that formulation of these well-known botanicals at a specific ratio perhaps may yield a composition with a much wider spectrum of mechanisms of actions to impact the multiple pathways involved in cellulite onset, continuation, or exacerbations.

SUMMARY

Cellulite represents one of the main esthetic concerns of women with a likely cause of psychological insecurities. Its pathophysiology involves multiple pathways that include vascular, adipose tissues, inflammation, structural and physiological.Treatment strategies for cellulite comprises increasing microcirculation flow, reducing lipogenesis, promoting lipolysis, free radicals scavenging or formation reduction, anti-inflammation and other invasive procedures.We screened our plant library for extracts that reduces cellular lipid accumulation, improves microcirculation, possesses high total antioxidant capacity, inhibits platelet aggregation, and moderates inflammation.Botanical extracts from Rosmarinus officinalis, Annona squamosa and Zanthoxylum clava-herculis were identified as leads and formulated to yield a standardized composition designated as UP1307 and suggested its usage for cellulite. Abbreviations Used: GMP: Good Manufacturing Practice; CA: Carnosic acid; NF-kB: nuclear factor-kB; HPLC: high-performance liquid chromatography; EtOH: Ethanol; DMEM: Dulbecco's modified Eagle's medium; FBS: fetal bovine serum; SD: Sprague Dawley; RAC: recto-anus coefficient; LPS: Lipopolysaccharide; DPPH: 1,1-diphenyl-2-picryl-hydrazyl; TNF-α: tumor necrosis factor; NO: Nitric oxide.

Pea aphid infestation induces changes in flavonoids, antioxidative defence, soluble sugars and sugar transporter expression in leaves of pea seedlings

The perception of aphid infestation induces highly coordinated and sequential defensive reactions in plants at the cellular and molecular levels. The aim of the study was to explore kinetics of induced antioxidative defence responses in leaf cells of Pisum sativum L.cv. Cysterski upon infestation of the pea aphid Acyrthosiphon pisum at varying population sizes, including accumulation of flavonoids, changes of carbon metabolism, and expression of nuclear genes involved in sugar transport. Within the first 96 h, after A. pisum infestation, flavonoid accumulation and increased peroxidase activity were observed in leaves. The level of pisatin increased after 48 h of infestation and reached a maximum at 96 h. At this time point, a higher concentration of flavonols was observed in the infested tissue than in the control. Additionally, strong post-infestation accumulation of chalcone synthase (CHS) and isoflavone synthase (IFS) transcription products was also found. The levels of sucrose and fructose in 24-h leaves infested by 10, 20, and 30 aphids were significantly lower than in the control. Moreover, in leaves infested by 30 aphids, the reduced sucrose level observed up to 48 h was accompanied by a considerable increase in the expression level of the PsSUT1 gene encoding the sucrose transporter. In conclusion, A. pisum infestation on pea leads to stimulation of metabolic pathways associated with defence.

Toxic and antifeedant activities of prenylated flavonoids isolated from Tephrosia apollinea L. against three major coleopteran pests of stored grains with reference to their structure-activity relationship

Four prenylated flavonoids, isoglabratephrin, (+)-glabratephrin, tephroapollin-F and lanceolatin-A, were isolated from Tephrosia apollinea L. and tested against three stored grain insects. Using the filter paper bioassay, compounds showed adulticidal activity against Sitophilus oryzae (L), Rhyzopertha dominica (F) and Tribolium castaneum (Herbst) at concentrations of 0.875, 1.75 and 3.5 mg mL(- 1). At 3.5 mg mL(- 1), tephroapollin-F was the most toxic (78.6%, 64.6% and 60.7% mortality was recorded after 10 days exposure of S. oryzae, R. dominica and T. castaneum, respectively). The F1 progeny production of insects was affected after parental exposure to flavonoids, where S. oryzae was the most susceptible. A nutritional bioassay, employing a flour disc and test concentrations of 0.65, 1.3 and 2.6 mg g(- 1), revealed a significant reduction in the relative growth rate, relative consumption rate and efficiency of conversion of ingested food by all insects. The structure-activity relationship among the tested flavonoids was discussed.

Polypharmacy (herbal and synthetic drug combination): a novel approach in the treatment of type-2 diabetes and its complications in rats

The aim of present study was to evaluate the effect of aqueous leaf extract of Annona squamosa with Glipizide in a high fat diet and streptozocin-induced type-2 diabetes. Nine groups (n = 6) of male Sprague-Dawley rats were used for the study, with. Basal blood glucose, urine volume, and body weights were measured and the rate were kept on a high fat diet. After 15 days, streptozocin in sub-diabetic dose (35 mg/kg) was administered to the animals to induce diabetes. With 1 week of consistent hyperglycemia, treatment was initiated. Aqueous extract of Annona squamosa was administered orally at 350 mg/kg body weight alone and in combination with reduced and reducing dose combinations of Glipizide. Blood glucose, body weight, urine volume were measured every 10th day. The elevated blood-glucose level in diabetic rats was controlled better with combination therapy compared with the synthetic drug alone or the herbal stand-alone drug. All the results were statistically significant (P < 0.001). A combination of Annona squamosa along with Glipizide may be helpful in dose reduction of Glipizide up to 50%, reducing the risk of the onset of insulin therapy.

Bioactivity of short-chain aliphatic ketones against adults of the granary weevil, Sitophilus granarius (L.)

BACKGROUND

The granary weevil, Sitophilus granarius (L.), is one of the most damaging pests of stored grains, causing severe quantitative and qualitative losses. Sustainable control means, alternative to the commonly used fumigants and broad-spectrum contact insecticides, are urgently needed owing to legislative limits, the development of resistant insect strains and increasing consumer demand for safe food. Short-chain aliphatic ketones, known to be emitted by cereal grains and previously identified as repellents to adult granary weevils, were evaluated for their ability to disrupt insect orientation towards wheat grains and as possible natural fumigants.

RESULTS

In behavioural bioassays, 2-pentanone, 2-hexanone, 2-heptanone and 2,3-butanedione significantly reduced insect orientation towards odours of wheat grains, with 2-hexanone and 2-heptanone being the most active. In fumigation tests, all compounds were effective in killing weevil adults, but they performed differently according to chemical structure, speed of action and presence of wheat grains. In the presence of grains, the highest fumigant toxicity was shown by 2-pentanone (LC(50) = 8.4 ± 1.0 mg L(-1)) after 24 h exposure, and by 2-pentanone (LC(50) = 4.5 ± 0.3 mg L(-1)), 2-heptanone (LC(50) = 7.1 ± 0.3 mg L(-1) ) and 2-hexanone (LC(50) = 8.1 ± 0.6 mg L(-1)) 1 week after the treatment end.

CONCLUSION

Short-chain aliphatic ketones have potential for applications in IPM programmes for the granary weevil because of their behaviour-altering activity and fumigant toxicity.

Efficacy of Annona squamosa on wound healing in streptozotocin-induced diabetic rats

Annona squamosa L. (Annonaceae), commonly known as custard apple, mainly used for its edible fruit, is also recognised with numerous medicinal properties. As there is no report on the efficacy of this plant for wound healing, we examined the efficacy of ethanolic extract of A. squamosa leaves on wound repair in streptozotocin-nicotinamide-induced diabetic rats. Open excision wounds were made on the back of rats. The drug at a dosage of 100 mg/kg body wt was reconstituted in 200 µl of phosphate buffered saline and applied topically once daily for the treated wounds. The control wounds were left untreated. Wound tissues formed on days 4, 8, 12 and 16 (post-wound) were used to estimate DNA, total protein, total collagen, hexosamine and uronic acid. Levels of lipid peroxides were also evaluated along with tensile strength and period of epithelialisation. A. squamosa L. increased cellular proliferation and collagen synthesis at the wound site as evidenced by increase in DNA, protein and total collagen. The treated wounds were observed to heal much faster as proved by enhanced rates of epithelialisation and wound contraction, which was also confirmed by histopathological examinations. The results strongly substantiate the beneficial effects of the topical application of A. squamosa L. in the acceleration of normal and diabetic wound healing.

N-Methyl-6, 7-dimethoxyisoquinolone in Annona squamosa twigs is the major immune modifier to elicit polarized Th1 immune response in BALB/c mice

Annona squamosa (AS) has traditionally been used as ethnomedicine. We have earlier extracted and fractionated the twigs of AS based upon its bioactivity and observed its immune potentiating activity that was localized in its three fractions. Present communication deals with the phytochemical analysis and pharmacological investigation of the most active chloroform fraction that led to isolation and identification of a number of compounds whose structures were elucidated using 1D and 2D NMR spectroscopic analysis. Amongst the twelve pure compounds isolated, five compounds Lanuginosine (1), (+)-O-methylarmepavine (2), (+)-anomuricine (3), Isocorydine (4), and N-methyl-6, 7-dimethoxyisoquinolone (5) were evaluated in vivo for their immune modifier activities in BALB/c mice after oral administration at three log doses of 0.3, 1.0 and 3.0mg/kg for 14 consecutive days. Of these, three compounds (1, 2 and 5) showed dose dependent immune stimulating activity. However, the uppermost activity was noted in the compound N-methyl-6, 7-dimethoxyisoquinolone at the 3.0mg/kg oral dose. The activity was assessed in the form of increased splenic T and B cellular proliferation, up-regulated CD4+, CD8+ and CD19+ cell population and accentuation in the peritoneal macrophage function. The compound possibly acted modifying the expression of Th1- and Th2- cytokines via stimulation of pro-inflammatory Th1 cytokines IL-2 and IFN-γ. These results warrant the use of the above compounds as an efficient immune-stimulant or immune-adjuvant against diseases with immune suppression. The analogs of the compound may further be chemically synthesized to achieve desired immune modifying activity.

Dialkoxybenzene and dialkoxyallylbenzene feeding and oviposition deterrents against the cabbage looper, Trichoplusia ni: potential insect behavior control agents

The antifeedant, oviposition deterrent, and toxic effects of individual dialkoxybenzene compounds/sets and of hydroxy- or alkoxy-substituted allylbenzenes, obtained through Claisen rearrangement of substituted allyloxybenzenes, were assessed against the cabbage looper, Trichoplusia ni , in laboratory bioassays. Most of the compounds/sets strongly deterred larval feeding, with some exhibiting mild toxic and oviposition deterrent effects as well. Some of the compounds/sets were more active than the commercial insect repellent, DEET (N,N-diethyl-m-toluamide), as both feeding and oviposition deterrents against the cabbage looper. On the basis of the obtained oviposition data a general hypothesis was proposed regarding the oviposition sites: one binding mode with the alkyl and allyl groups on the same side of the benzene ring resulted in deterrence, the other with alkyl and allyl groups on opposite sides of the benzene ring resulted in stimulation. The results suggest some structure-activity relationships useful in improving the efficacy of the compounds and designing new, nontoxic insect control agents for agriculture.

Plant metabolites: an alternative and sustainable approach towards post harvest pest management in pulses

Grain legumes are an important source of proteins in vegetarian diet besides their role in biological nitrogen fixation. They are prone to heavy pest infestation both on and off the field. Pest associated losses are an important contributing factor towards declining per capita availability of grain legumes. Synthetic chemical pesticides have played an important role in crop preservation, however their incessant use has posed several environmental and human health concerns. Methyl bromide and phosphine are commonly used for the post harvest preservation of grain legumes. However, the former has to be phased out by 2015 as per the Montreal protocol whereas the latter is showing development of resistance to it by the insects. In the light of this, alternative, safer and sustainable strategies are needed for crop protection. Plants can serve as a rich source of bioactive chemicals for this purpose. Both primary as well as secondary metabolites can be evaluated against the target pests. The paper reviews the status of research in the area of use of plant metabolites in post harvest pest management of grain legumes.

Antidiabetic and antioxidative effects of Annona squamosa leaves are possibly mediated through quercetin-3-O-glucoside

Present investigation was made to reveal the involvement of a quercetin in the antidiabetic and antiperoxidative effects of Annona squamosa leaf extract. Quercetin-3-O-glucoside (characterized by UV, IR, MS and NMR analyses) was isolated from Annona squamosa leaves and examined for its potential to regulate alloxan-induced hyperglycemia and lipid peroxidation (LPO) in rats. While in alloxan treated animals, an increase in the concentration of serum glucose with a parallel decrease in insulin level was observed, administration of 15 mg/kg/day of isolated quercetin-3-O-glucoside for 10 consecutive days to the hyperglycemic animals reversed these effects and simultaneously inhibited the activity of hepatic glucose-6-phosphatase. It further decreased the hepatic and renal LPO with a concomitant increase in the activities of antioxidative enzymes, such as catalase (CAT) and superoxide dismutase (SOD) and in glutathione (GSH) content, indicating its safe and antiperoxidative effects. These findings suggest the potential of quercetin-3-O-glucoside in the amelioration of diabetes mellitus and tissue lipid peroxidation. It also appears that the antidiabetic effects of A. squamosa leaf extract is possibly mediated through the insulin stimulating and/or free radical scavenging properties of its active constituent, quercetin-3-O-glucoside.

Hypoglycemic and antidiabetic effect of ethanolic extract of leaves of Annona squamosa L. in experimental animals

The ethanolic extract of Annona squamosa L. (Annonaceae) leaves was administered orally at different doses to normal as well as streptozotocin (STZ)-induced diabetic rats and alloxan-induced diabetic rabbits. The dose of 350 mg/kg body weight (bw) reduced the fasting blood glucose (FBG) level by 6.0% within 1 h, whereas, the peak blood glucose at 1 h during glucose tolerance test (GTT) was reduced by 17.1% in normal rats. The same dose of ethanolic extract reduced FBG by 26.8% and improved glucose tolerance by 38.5 and 40.6% at 1 and 2 h, respectively, during GTT in alloxan-induced diabetic rabbits. In STZ-diabetic rats, a fall of 13.0% in FBG and an improvement in glucose tolerance by 37.2 and 60.6% at 1 and 2 h, respectively, was observed during GTT. The dose of 350 mg/kg bw of ethanolic extract in 10-day treatment of a group of STZ-diabetic rats produced 73.3% fall in FBG level and no sugar was observed in fasting urine. Treatment of severely-diabetic rabbits for 15 days with a dose of 350 mg/kg of extract reduce FBG by 52.7% and urine sugar by 75%. It brought about fall in the level of total cholesterol (TC) by 49.3% with increase of 30.3% in high-density lipoprotein (HDL) and decrease of 71.9 and 28.7% in low-density lipoprotein (LDL) and triglycerides (TG) levels, respectively.

Insecticidal action of the polyphenolic rich fractions from the stem bark of Streblus asper on Dysdercus cingulatus

Extracts from the stem bark of Streblus asper possess insecticidal activity against the fifth instar of Dysdercus cingulatus. Methanolic extract showed an LC(50) value of 5.56 microg/insect. Partition with chloroform increased the insecticidal activity (LC(50) 2.01 microg/insect). Three polyphenolic rich fractions were obtained from silica-gel column chromatography of the chloroform fraction and found to have noteworthy insecticidal activity (LC(50): 1.82 microg, 2.70 microg, 2.26 microg/insect) by topical application. This may provide a useful beginning for the development of biopesticides.

Partial characterization and insecticidal properties of Ricinus communis L foliage flavonoids

Aqueous leaf extract of Ricinus communis L (Euphorbiaceae), a cultivated plant in tropical countries, showed excellent insecticidal activity against Callosobruchus chinensis L (Coleoptera: Bruchidae). We have isolated and tested flavonoids as insecticidal and antimicrobial agents. The isolated flavonoids showed potential insecticidal, ovicidal and oviposition deterrent activities against C chinensis L. However, antimicrobial activity against the common microbial infestants of stored pulses, of which C chinensis is a major pest, was found to be insignificant. Two bands having Rf 0.63 and 0.69 were seen on HPTLC plates using mobile phase benzene + ethyl acetate + methanol + formic acid (12 + 4.5 + 2 + 1.5 by volume) as eluant. The Rf values and scanning of the spectrum in the ultraviolet region, showed identity with the flavonoids quercetin and kaempferol. This was further confirmed using HPLC and IR and UV spectrometry. HPLC and HPTLC chromatograms also suggested quercetin to be the major flavonoid present in the hydrolyzed aqueous leaf extract of R communis.