Journal of Pharmacognosy & Natural Products

Ivermectin and moxidectin are the only recommended drugs for the treatment of onchocerciasis, with the former being the most widely used. However, both drugs are not suitable in eliminating the disease. There is the need to identify novel anti-onchocercal agents including from plant sources. This project investigated the anti-onchocercal activity of extracts of Azadirachta indica that could eventually yield new drug leads for the cure of onchocerciasis. Organic extracts were obtained from the leaves and seeds of Azadirachta indica using solvents of different polarities and tested in vitro against two developmental stages of the bovine model parasite, Onchocerca ochengi. Both microfilariae (mf) and adult male worm viabilities were assessed by motility reduction, while adult female worm viability was evaluated using the standard MTT/formazan assay. Toxicity of active extracts was assessed on monkey kidney epithelial cells (LLC-MK2) and in BALB/c mice. The methylene chloride extract of the leaves was the most active against the adult female worms and the mf with IC_50s of 55.61 μg/ml and 8.048 μg/ml respectively. The hexane extract of the leaves was the most active against the adult male worms with an IC₅₀ of 16.34 μg/ml. Selectivity indices for the most active extracts were 1.12 for adult females, 7.77 for the mf and 7.35 for adult males indicating that the extracts are selectively active on the parasites. The most active extracts showed no acute toxicity to Balb/c mice and had no significant effect on the liver enzymes, alanine aminotransferase and aspartate aminotransferase and markers of kidney function, urea and creatinine (p<0.05). Phytochemical analysis revealed the presence of saponins, flavonoids, steroids, tannins, alkaloids, polyphenols and terpenoids. The anti-onchocercal activity and selectivity indices of A. indica extracts suggest the plant is a potential source of new anti-onchocercal drug leads justifying further investigations for the identification and isolation of the bioactive compounds.

Herbal mosquito repellent is a promising alternative to overcome the drawbacks of conventional mosquito repellents containing N, N-diethyl metatoluamide. The liposomal gel has a propensity for keratinizing the skin's horny layer and can penetrate deeper into the skin for enhanced absorption and is therapeutically effective and less toxic than other topical dosage forms, resulting in prolonged and controlled extract release. Vitex negundo (Chaste tree) leaves were dried and mechanically powdered. The powder was extracted with ethanol and distilled water (1:1), then the solvent was removed, dried using a lyophilization process, and stored. The phytochemical and composition analysis of the plant extract was done. The hydration process is carried out at a temperature of 40°C. Liposomal gel was prepared using the thin film hydration methods. A suitable base concentration was used to adjust the pH of the topical gel (6.5 –7.5). The liposomal dispersions were characterized for particle size distribution, SEM, XRD, ATR-FTIR, entrapment efficiency, in-vitro release study, and stability study. The liposomal gel was evaluated for colour, appearance, smoothness, Washability, skin irritation study, and Mosquito repellent activity. The developed formulations showed continuous extract release over 8 hours, extending the medication's residence time. The prepared optimized gel formulation was clear and stable after 90 days of storage under accelerated stability conditions. The mosquito-repellent activity of the optimized gel formulation was investigated using the arm-in-cage methodology. The field trials of the optimized gel were performed at 30, 60, 120, and 180 minutes, demonstrating excellent mosquito repellency. The total number of mosquitoes that landed was counted in a triplicate manner. The results of the present study revealed that Vitex negundo extract loaded mosquito repellent liposomal gel could produce fewer side effects, inexpensive, more effective, and long-lasting more than 10 hours to prevent mosquito-borne diseases like malaria, dengue, and chikungunya.

Chemical ecology is a multidisciplinary field that explores the chemical interactions between organisms and their environment. It delves into the chemical signals that shape ecological interactions, driving processes such as communication, defense and competition among organisms. Within this intricate web of interactions lies a treasure trove of natural compounds with potential applications in medicine, agriculture and industry. Chemical ecology focuses on the chemical compounds produced by organisms and their roles in ecological interactions. These compounds can serve various functions, including communication, defense against predators, attraction of mates and competition for resources. For example, pheromones are chemical signals used by organisms to communicate with members of the same species, playing crucial roles in mating, territory marking and aggregation. Communication lies at the heart of many ecological interactions and chemical signals play a significant role in this process. Organisms release volatile compounds into the environment, which can be detected by other individuals, often over long distances. These chemical signals can convey information about mating availability, territory ownership, or the presence of predators or prey. For instance, plants release Volatile Organic Compounds (VOCs) to attract pollinators or to defend against herbivores.

In the realm of natural product discovery, where the bounty of nature holds untold treasures, collaboration emerges as a beacon guiding researchers, industries and conservationists towards shared goals. Nature has long been humanity's foremost pharmacist, offering a rich repertoire of compounds with therapeutic potential. From the rainforests to the depths of the oceans, diverse ecosystems harbor an abundance of plant, microbial and marine species, each a potential source of novel bioactive molecules. However, unlocking this potential requires a multidisciplinary approach that transcends traditional boundaries. Academic institutions serve as the vanguards of scientific inquiry, driving fundamental research and nurturing the next generation of scientists. Within the realm of natural product discovery, academia plays a pivotal role in elucidating the chemical diversity of organisms and unraveling their pharmacological properties. Through interdisciplinary collaborations, researchers combine expertise in chemistry, biology and pharmacology to identify and characterize bioactive compounds.

The quest for novel drugs and therapeutic agents has always been a central pursuit in medical science. Throughout history, nature has served as an abundant source of inspiration for pharmaceutical research, with plants emerging as a treasure trove of bioactive compounds. Among the various classes of natural products, secondary metabolites have garnered significant attention due to their diverse chemical structures and pharmacological activities. Secondary metabolites are organic compounds synthesized by plants, fungi and bacteria, which are not directly involved in primary metabolic processes such as growth and development but play crucial roles in ecological interactions and defense mechanisms. These compounds exhibit remarkable structural diversity, ranging from simple phenolic compounds to complex alkaloids and terpenoids. Secondary metabolites often possess pharmacological properties, making them valuable resources for drug discovery and development.

The Earth is adorned with an intricate tapestry of life, with ecosystems ranging from lush rainforests to vast oceans, each harboring a treasure trove of biodiversity. Within these ecosystems lie natural product gems—bioactive compounds sourced from plants, animals and microorganisms—that hold immense potential for pharmaceuticals, cosmetics and beyond. Rainforests, often referred to as the "lungs of the Earth," are biodiversity hotspots that cover only 6% of the planet's surface but are home to more than half of all known species. Within these dense canopies and rich forest floors lie a plethora of plant species, many of which have been used for centuries by indigenous cultures for medicinal purposes. One such example is the Amazon rainforest, which boasts unparalleled biodiversity and is a veritable treasure trove of natural product gems. From the bark of the cinchona tree, indigenous peoples derived quinine, a compound used to treat malaria. Similarly, the rosy periwinkle plant, native to Madagascar, yielded compounds that led to the development of drugs for leukemia and Hodgkin's disease.

Natural products have long served as a cornerstone in drug discovery, providing a rich source of chemical diversity and biological activity. However, the traditional methods of isolating and synthesizing these compounds often involve environmentally harmful processes, leading to significant concerns regarding sustainability and ecological impact. In recent years, the principles of green chemistry have emerged as a promising framework for transforming natural product discovery and drug development into more sustainable practices. By integrating green chemistry principles into every stage of the drug discovery process, researchers can minimize waste, reduce energy consumption and mitigate environmental impact while still harnessing the potential of natural products for therapeutic applications.

Natural products, compounds derived from living organisms, have long been invaluable sources of pharmaceuticals, agrochemicals and other biologically active molecules. Historically, their discovery relied heavily on labor-intensive processes such as bioassay-guided fractionation. However, with the advent of the digital age, the landscape of natural product discovery has undergone a significant transformation. Big data and bioinformatics have emerged as powerful tools, revolutionizing the way researchers identify, isolate and characterize novel natural products. Natural products have been a prolific source of biologically active compounds, with many serving as the basis for pharmaceuticals and agrochemicals. Their structural complexity and diverse chemical scaffolds make them valuable starting points for drug development. However, traditional methods of natural product discovery are often time-consuming, resource-intensive and limited by the vastness of natural biodiversity.

In an age marked by technological advancement and scientific innovation, the allure of natural products and traditional medicine persists as a testament to the enduring wisdom of our ancestors. From ancient herbal remedies to indigenous healing practices, traditional medicine has served as a cornerstone of human health and wellness for millennia. Today, amidst growing concerns over the side effects of synthetic drugs and the unsustainable practices of modern healthcare, there is a resurgence of interest in natural products and traditional healing modalities. The roots of traditional medicine can be traced back to the dawn of human civilization, where ancient cultures developed sophisticated systems of healing based on the medicinal properties of plants, minerals and animal-derived substances. In ancient Egypt, for example, medicinal herbs such as aloe vera and garlic were revered for their healing properties, while in traditional Chinese medicine, acupuncture and herbal remedies formed the cornerstone of healthcare practices. Similarly, indigenous cultures around the world, from the Amazon rainforest to the Australian outback, have long relied on the knowledge of local plants and traditional healing rituals to maintain health and vitality.

Herbal medicine, rooted in centuries-old traditions, has long been a cornerstone of healthcare practices worldwide. Its efficacy and safety have been supported by anecdotal evidence and cultural heritage. Central to the potency of many herbal remedies are secondary metabolites— bioactive compounds produced by plants for various purposes, including defense against predators and environmental stresses. These secondary metabolites have garnered significant attention in recent years, not only for their therapeutic potential but also for their role in bridging traditional herbal medicine with modern scientific approaches. Secondary metabolites, also known as natural products, are organic compounds synthesized by plants, fungi and bacteria that are not essential for their primary metabolic processes but serve crucial ecological functions. These compounds exhibit a remarkable diversity in structure and function, ranging from alkaloids and terpenoids to flavonoids and phenolic compounds. Each class of secondary metabolites possesses unique chemical properties and biological activities, making them valuable resources for drug discovery and medicinal applications.