Insecticidal Constituents and Activity of Alkaloids from Cynanchum mongolicum

Potential applications of antofine and its synthetic derivatives in cancer therapy: structural and molecular insights

Cancer is a major global health challenge, being the second leading cause of morbidity and mortality after cardiovascular disease. The growing economic burden and profound psychosocial impact on patients and their families make it urgent to find innovative and effective anticancer solutions. For this reason, interest in using natural compounds to develop new cancer treatments has grown. In this respect, antofine, an alkaloid class found in Apocynaceae, Lauraceae, and Moraceae family plants, exhibits promising biological properties, including anti-inflammatory, anticancer, antiviral, and antifungal activities. Several molecular mechanisms have been identified underlying antofine anti-cancerous effects, including the inhibition of nuclear factor κB (NF-κB) and AKT/mTOR signaling pathways, epigenetic inhibition of protein synthesis, ribosomal targeting, induction of apoptosis, inhibition of DNA synthesis, and cell cycle arrest. This study discusses the molecular structure, sources, photochemistry, and anticancer properties of antofine in relation to its structure-activity relationship and molecular targets. Then, examine in vitro and in vivo studies and analyze the mechanisms of action underpinning antofine efficacy against cancer cells. This review also discusses multidrug resistance in human cancer and the potential of antofine in this context. Safety and toxicity concerns are also addressed as well as current challenges in antofine research, including the need for clinical trials and bioavailability optimization. This review aims to provide comprehensive information for more effective natural compound-based cancer treatments.

Arecoline inhibits the growth of Spodoptera litura by inducing intestinal metabolic dysfunction

Arecoline (ACL), an active constituent derived from Areca catechu L., exerts various pharmacological effects and serves as a potential plant-based insecticide. However, the effects of ACL on Spodoptera litura, an important and widely distributed agricultural pest, remain unknown. This study aimed to elucidate the mechanism underlying ACL-induced toxicity and its inhibitory effects on larval growth and development through intestinal pathology observations, intestinal transcriptome sequencing, intestinal digestive enzyme activity analysis. The results indicated that ACL exposure leads to pathological alterations in the S. litura midgut. Furthermore, the detection of digestive enzyme activity revealed that ACL inhibits the activities of acetyl CoA carboxylase, lipase, α-amylase, and trypsin. Simultaneously, upregulation of superoxide dismutase activity and downregulation of malondialdehyde levels were observed after ACL exposure. Transcriptome analysis identified 1118 genes that were significantly differentially expressed in the midgut after ACL exposure, potentially related to ACL toxic effects. Notably, ACL treatment downregulated key enzymes involved in lipid metabolism, such as fatty acid binding protein 2-like, pancreatic triacylglycerol lipase-like, pancreatic lipid-related protein 2-like, and fatty acid binding protein 1-like. Taken together, these results suggest that ACL induces midgut damage and impedes larval growth by suppressing digestive enzyme activity in the intestine. These findings can aid in the development of environmentally friendly plant-derived insecticides, utilizing ACL to effectively combat S. litura proliferation.

Mass spectrometry-based metabolomics for the elucidation of alkaloid biosynthesis and function in invasive Vincetoxicum rossicum populations

The genus Vincetoxicum includes a couple of highly invasive vines in North America that threaten biodiversity and challenge land management strategies. Vincetoxicum species are known to produce bioactive phenanthroindolizidine alkaloids that might play a role in the invasiveness of these plants via chemical interactions with other organisms. Untargeted, high-resolution mass spectrometry-based metabolomics approaches were used to explore specialized metabolism in Vincetoxicum plants collected from invaded sites in Ontario, Canada. All metabolites corresponding to alkaloids in lab and field samples of V. rossicum and V. nigrum were identified, which collectively contained 25 different alkaloidal features. The biosynthesis of these alkaloids was investigated by the incorporation of the stable isotope-labelled phenylalanine precursor providing a basis for an updated biosynthetic pathway accounting for the rapid generation of chemical diversity in invasive Vincetoxicum. Aqueous extracts of aerial Vincetoxicum rossicum foliage had phytotoxic activity against seedlings of several species, resulting in identification of tylophorine as a phytotoxin; tylophorine and 14 other alkaloids from Vincetoxicum accumulated in soils associated with full-sun and a high-density of V. rossicum. Using desorption-electrospray ionization mass spectrometry, 15 alkaloids were found to accumulate at wounded sites of V. rossicum leaves, a chemical cocktail that would be encountered by feeding herbivores. Understanding the specialized metabolism of V. rossicum provides insight into the roles and influences of phenanthroindolizidine alkaloids in ecological systems and enables potential, natural product-based approaches for the control of invasive Vincetoxicum and other weedy species.

Alkaloids in food: a review of toxicity, analytical methods, occurrence and risk assessments

Alkaloids have been utilized by humans for years. They have diverse applications in pharmaceuticals. They have been proven to be effective in treating a number of diseases. They also form an important part of regular human diets, as they are present in food items, food supplements, diet ingredients and food contaminants. Despite their obvious importance, these alkaloids are toxic to humans. Their toxicity is dependent on a range of factors, such as specific dosage, exposure time and individual properties. Mild toxic effects include nausea, itching and vomiting while chronic effects include paralysis, teratogenicity and death. This review summarizes the published studies on the toxicity, analytical methods, occurrence and risk assessments of six major alkaloid groups that are present in food, namely, ergot, glycoalkaloids, purine, pyrrolizidine, quinolizidine and tropane alkaloids.

Analysis of glutathione-S-transferases from larvae of Galleria mellonella (Lepidoptera, Pyralidae) with potential alkaloid detoxification function

The greater wax moth, Galleria mellonella, is a global pest for beehives, doing damage in the larval stage. Although a significant number of studies have reported on larvae and adults, to date no effective pest control has been implemented. In this study, we tested larval resistance to alkaloids from Berberis microphylla, and the objective was to identify enzymes that participate in alkaloid detoxification through enzymatic assays, bioinformatics analysis and qRT-PCR. Findings suggest glutathione-S-transferases (GSTs), from an increased metabolic mechanism, are responsible for alkaloid detoxification rather than cytochrome P450 (CYP), carboxylesterases (CarE). A bioinformatics analysis from transcriptome data revealed 22 GSTs present in both G. mellonella larvae and adults. The qRT-PCR experiments corroborated the presence of the 22 GSTs in larvae, where GST8 and GST20 stood out with the highest expression after berberine treatment. Structural information around GST8 and GST20 suggests that GST8 could bind berberine stronger than GST20. These findings represent an important advance in the study of detoxification enzymes in G. mellonella, expanding the role of delta-class GSTs towards alkaloids. Likewise, GST inhibition by alkaloid analogs is proposed in the framework of integrated pest management strategies.

Antioxidant and Anti-Inflammatory Activity of Cynanchum acutum L. Isolated Flavonoids Using Experimentally Induced Type 2 Diabetes Mellitus: Biological and In Silico Investigation for NF-κB Pathway/miR-146a Expression Modulation

Cynanchum acutum L. is a climbing vine that belongs to the family Apocynaceae. Using different chromatographic techniques, seven compounds were isolated from the methanolic extract of the plant. The isolated compounds include six flavonoid compounds identified as rutin (1), quercetin-3-O-neohesperidoside (2), quercetin-3-O-β-galactoside (3), isoquercitrin (4), quercetin (5), and kaempferol 3-O-β-glucoside (6), in addition to a coumarin, scopoletin (7). The structures of the compounds were elucidated based on 1D NMR spectroscopy and high-resolution mass spectrometry (HR-MS), and by comparison with data reported in the literature. The first five compounds were selected for in vivo investigation of their anti-inflammatory and antioxidant properties in a rat model of type 2 diabetes. All tested compounds significantly reduced oxidative stress and increased erythrocyte lysate levels of antioxidant enzymes, along with the amelioration of the serum levels of inflammatory markers. Upregulation of miR-146a expression and downregulation of nuclear factor kappa B (NF-κB) expression were detected in the liver and adipose tissue of rats treated with the isolated flavonoids. Results from the biological investigation and those from the validated molecular modeling approach on two biological targets of the NF-κB pathway managed to highlight the superior anti-inflammatory activity of quercetin-3-O-galactoside (3) and quercetin (5), as compared to other bioactive metabolites.

Activity of Some Plant and Fungal Metabolites towards Aedes albopictus (Diptera, Culicidae)

Aedes albopictus (Skuse) is a widespread mosquito, a vector of important human arboviruses, including Chikungunya, Dengue and Zika. It is an extremely difficult species to control even for the onset of resistances to chemicals insecticides, therefore ecofriendly products are urgently needed. In this study, the activity of Amaryllidaceae alkaloids and some of their semisynthetic derivatives, of 2-methoxy-1,4-naphthoquinone and two analogues, of cyclopaldic acid and epi-epoformin on the survival and development of Ae. albopictus larvae was evaluated. First-instar larval exposure for 24 and 48 h to cyclopaldic acid, resulted in mortality mean per-centage of 82.4 and 96.9 respectively; 1,2-O,O-diacetyllycorine 48h post-treatment caused 84.7% mortality. Larval and pupal duration were proved to decrease significantly when larvae were exposed to cyclopaldic acid, 1,2-O,O-diacetyllycorine and N-methyllycorine iodide. The mean number of third-instar larvae surviving to 2-methyl-1,4-naphthoquinone, 2-hydroxy-1,4-naphthoquinone and 2-methoxy-1,4-naphthoquinone was significantly lower than the number of correspondent control larvae over the time. This study indicated that 1,2-O,O'-diacetyllycorine, N-methyllycorine iodide, cyclopaldic acid and 1,4-naphthoquinone structural derivatives have good potential for developing bioinsecticides for mosquito control programs. The obtained results are of general interest due to the global importance of the seri-ous human diseases such a vector is able to spread.

Comparative Metabolic Profiling in Pulp and Peel of Green and Red Pitayas (Hylocereus polyrhizus and Hylocereus undatus) Reveals Potential Valorization in the Pharmaceutical and Food Industries

Pitaya (Hylocereus genus) is a popular plant with exotic and nutritious fruit, which has widespread uses as a source of nutrients and raw materials in the pharmaceutical industry. However, the potential of pitaya peel as a natural source of bioactive compounds has not yet fully been explored. Recent advances in metabolomics have paved the way for understanding and evaluating the presence of diverse sets of metabolites in different plant parts. This study is aimed at exploring the diversity of primary and secondary metabolites in two commercial varieties of pitaya, i.e., green pitaya (Hylocereus undatus) and red pitaya (Hylocereus polyrhizus). A total of 433 metabolites were identified using a widely targeted metabolomic approach and classified into nine known diverse classes of metabolites, including flavonoids, amino acids and its derivatives, alkaloids, tannins, phenolic acids, organic acids, nucleotides and derivatives, lipids, and lignans. Red pitaya peel and pulp showed relatively high accumulation of metabolites viz. alkaloids, amino acids and its derivatives, and lipids. Differential metabolite landscape of pitaya fruit indicated the presence of key bioactive compounds, i.e., L-tyrosine, L-valine, DL-norvaline, tryptophan, γ-linolenic acid, and isorhamnetin 3-O-neohesperidoside. The findings in this study provide new insight into the broad spectrum of bioactive compounds of red and green pitaya, emphasizing the valorization of the biowaste pitaya peel as raw material for the pharmaceutical and food industries.

Cabbage Production in West Africa and IPM with a Focus on Plant-Based Extracts and a Complementary Worldwide Vision

In urban and peri-urban areas in West Africa, the cabbage Brassica oleracea L. (Brassicaceae) is protected using repeated high doses of synthetic insecticides. After a brief description of available IPM components, this paper presents a literature review focused on the botanical extracts that have been experimented with at the laboratory or in the field in West Africa against major cabbage pests. The literature reviewed mentions 19 plant species from 12 families used for cabbage protection in the subregion. The species most used are Azadirachta indica, Capsicum frutescens, Ocimum gratissimum and Ricinus communis. An overview of the world literature showed that a total of 13 plant species belonging to 8 families used to control cabbage pests are reported from the rest of Africa, and 140 plant species belonging to 43 families from the rest of the world. The most commonly used and tested plant species against insect pests in the three geographical areas considered is A. indica.

Fractionated Extracts From Gnidia kraussiana (Malvales: Thymeleaceae) as Bioactive Phytochemicals for Effective Management of Callosobruchus maculatus (Coleoptera: Chrysomelidae) in Stored Vigna unguiculata (Fabales: Fabaceae) Seeds

One of the most important global problems is protecting food from insect pests. The negative effects of synthetic insecticides on human health led to a resurgence of interest in botanical insecticides due to their minimal ecological side effects. Therefore, the insecticidal potential of hexane, acetone, and methanol extracts of Gnidia kraussiana Meisn roots at 1 and 5g/kg, and neem seed oil (NSO), used as standard insecticide, were evaluated. Ovicidal and larvicidal toxicity was tested by treating freshly laid eggs and larvae at different immature stages of Callosobruchus maculatus (F.). Cowpea (Vigna unguiculata) (L.) Walp seed damage and weight loss were assessed after a storage period of 4 mo. Repellency effects were detected in choice test using a linear olfactometer. All the fractions were toxic to C. maculatus; however, their bioactivities were inversely correlated with products polarity. Extracts proved to be more toxic than the commercial NSO. The acetone extract was more effective against immature stages of C. maculatus than the methanol extract; eggs, first-, and second-instar larvae being the more susceptible. No cowpea seed damage and weight loss were recorded from the seeds treated with hexane and acetone extracts at the dosage of 5 g/kg, after 4 mo of storage. Extracts evoked stronger repellency effects compared with the tested standard insecticide. According to the above, hexane and acetone extracts are good candidates for incorporation in integrated pest management programs for the control of C. maculatus in stored cowpea seeds.

Larvicidal Activity of Ethyl Acetate Extract of Derris elliptica Root against the Third-Instar Larvae of Cypermethrin-Resistant Aedes aegypti Offspring

Background:

Derris elliptica extracts have a high larvicidal potential against the laboratory strain of Aedes aegypti larvae, but the effect on offspring larvae of pyrethroid-resistant strains of the species is lack understood. This study aimed to determine the larvicidal activity of the ethyl acetate extract of tuba root against the third-instar larvae of the Cypermethrin-resistant Ae. aegypti offspring.

Methods:

The experimental study occupied four levels of ethyl acetate extract of D. elliptica namely 10, 25, 50, and 100 ppm, and each level was four times replicated. As many as twenty of healthy third-instar larvae, offspring of Cypermethrin-resistant Ae. aegypti were subjected to each experiment group. Larval mortality rate and lethal concentration 50% subject (LC₅₀) were calculated after 24 and 48 hours of exposure time.

Results:

Mortality of larvae increased directly proportional to the increase of extract concentration. Larval mortality rates after 24 and 48 hours of exposure were 40–67.5% and 62.5–97.5%, and LC₅₀ were 34.945 and 6.461ppm, respectively.

Conclusion:

The ethyl acetate extract of D. elliptica has the high effectiveness larvicidal potential against the third-instar larvae, offspring of the Cypermethrin-resistant Ae. aegypti. Isolation of the specific compound is necessarily done to obtain the active ingredient for larvicide formulation.

Possible pharmaceutical applications can be developed from naturally occurring phenanthroindolizidine and phenanthroquinolizidine alkaloids

Naturally occurring phenanthroindolizidine and phenanthroquinolizidine alkaloids (PIAs and PQAs) are two small groups of herbal metabolites sharing a similar pentacyclic structure with a highly oxygenated phenanthrene moiety fused with a saturated or an unsaturated N-heterocycle (indolizidine/quinolizidine moieties). Natural PIAs and PQAs only could be obtained from finite plant families (such as Asclepiadaceae, Lauraceae and Urticaceae families, etc.). Up to date, more than one hundred natural PIAs, while only nine natural PQAs had been described. PIA and PQA analogues have been applied to the development of potent anticancer agents all along because of their excellent cytotoxic activity. However, in the last two decades, other great biological properties, such as anti-inflammatory and antiviral activities were revealed successively by different pharmacological assays. Especially because of their potent antiviral activity against coronavirus (TGEV, SARS CoV and MHV) and tobacco mosaic virus, PIA and PQA analogues have attracted much pharmaceutical attention again, some of them have been used to present interesting targets for total or semi synthesis, and structure-activity relationship (SAR) study for the development of antiviral agents. In this review, natural PIA and PQA analogues obtained in the last two decades with their herbal origins, key spectroscopic characteristics for structural identification, biological activity with possible SARs and application prospects were systematically summarized. We hope this paper can stimulate further investigations on PIA and PQA analogues as an important source for potential drug discovery.

Mutagenicity, cytotoxic and antioxidant activities of Ricinus communis different parts

Ricinus communis (castor plant) is a potent medicinal plant, which is commonly used in the treatment of various ailments. The present study was conducted to appraise the cytotoxicity and mutagenicity of R. communis along with antioxidant and antimicrobial activities. Cytotoxicity was evaluated by hemolytic and brine shrimp assays, whereas Ames test (TA98 and TA100) was used for mutagenicity evaluation. Plant different parts were extracted in methanol by shaking, sonication and Soxhlet extraction methods. The R. communis methanolic extracts showed promising antioxidant activity evaluated as through total phenolic contents (TPC), total flavonoid content (TFC), DPPH free radical inhibition, reducing power and inhibition of linoleic acid oxidation. R. communis seeds, stem, leaves, fruit and root methanolic extracts showed mild to moderate cytotoxicity against red blood cells (RBCs) of human and bovine. Brine shrimp lethality also revealed the cytotoxic nature of extracts with LC50 in the range of 0.22-3.70 (µg/mL) (shaking), 1.59-60.92 (µg/mL) (sonication) and 0.72-33.60 (µg/mL) (Soxhlet), whereas LC90 values were in the range of 345.42-1695.81, 660.50-14,794.40 and 641.62-15,047.80 µg/mL for shaking, sonication and Soxhlet extraction methods, respectively. R. communis methanolic extracts revealed mild mutagenicity against TA98 (range 1975 ± 67 to 2628 ± 79 revertant colonies) and TA100 (range 2773 ± 92 to 3461 ± 147 revertant colonies) strains and these values were 3267 ± 278 and 4720 ± 346 revertant colonies in case of TA98 and TA100 positive controls, respectively. R. communis methanolic extracts prevented the H2O2 and UV to Plasmid pBR322 DNA oxidative damage. Results revealed that R. communis is a potential source of bioactive compounds and in future studies the bioactive compounds will be identified by advanced spectroscopic techniques.

A Novel Insecticidal Peptide SLP1 Produced by Streptomyces laindensis H008 against Lipaphis erysimi

Aphids are major insect pests for crops, causing damage by direct feeding and transmission of plant diseases. This paper was completed to discover and characterize a novel insecticidal metabolite against aphids from soil actinobacteria. An insecticidal activity assay was used to screen 180 bacterial strains from soil samples against mustard aphid, Lipaphis erysimi. The bacterial strain H008 showed the strongest activity, and it was identified by the phylogenetic analysis of the 16S rRNA gene and physiological traits as a novel species of genus Streptomyces (named S. laindensis H008). With the bioassay-guided method, the insecticidal extract from S. laindensis H008 was subjected to chromatographic separations. Finally, a novel insecticidal peptide was purified from Streptomyces laindensis H008 against L. erysimi, and it was determined to be S-E-P-A-Q-I-V-I-V-D-G-V-D-Y-W by TOF-MS and amino acid analysis.