Current Traditional Medicine - Volume 7, Issue 1, 2021

Heterocyclic compounds constitute one of the largest and most versatile families of organic compounds. There are many heterocyclic compounds that are being isolated from natural sources and day by day the number is increasing rapidly due to their enormous utility. Nitrogen containing heterocyclic compounds have a prominent role in medicinal chemistry, biochemistry and other streams of science. In this review, we have covered most of the biologically active nitrogen containing heterocyclic compounds obtained from the natural sources including indole, carbazole, quinoline, isoquinoline and benzothiazole ring system. These isolated nitrogen containing heterocyclic compounds render wide spectrum of biological activities including antifungal, anti-inflammatory, antibacterial, antioxidants, anticonvulsant, anti-allergic, herbicidal and anticancer activities.

Natural products provide cornucopia of heterocyclic systems. The nucleus of 2- phenyl chromane is one of the important and well-known heterocycles found in the natural products. Naringenin, a plant-derived flavanone (2-phenyl chroman-4-one) belongs to the family of flavanoids. It possesses diverse biologic activities such as antidiabetic, antiatherogenic, antidepressant, antiandrogenic, antiestrogenic, immunomodulatory, antitumor, antimicrobial, anti-inflammatory, antiviral, hypolipidemic, antihypertensive, antioxidant, neuroprotective, anti-obesity, anti-Alzheimer, and memory enhancer activity. It has the potential to be used as an active pharmacophore. There have been reports of a number of molecular mechanisms underlying their beneficial activities. With emerging interest in traditional medicine and exploiting their potential based on a variety of health care systems, naringenin literature was thought to be explored. Further, this review aims to provide a new era of flavonoid-based therapeutic agents with new insights into naringenin and its derivatives as a lead compound in drug design.

Natural products are well known for their therapeutic properties. The primary reason for their therapeutic effectiveness is the presence of secondary plant metabolites like alkaloids, glycosides, flavonoids etc. All these metabolites are generally classified as per their chemical structures. Similarly, diversified alkaloids are classified as per the chemical moieties like indole, quinoline, Isoquinoline, indolizine etc. Alkaloids having indolizidine moiety are well known for their biological actions. In this review, indolizidine alkaloids like antofine, castanospermine, swainsonine, tylophorine, gephyrotoxins, lentiginosine, pergularinine etc. and their derivatives have been discussed. Furthermore, important points related to the structure-activity relationship of selected alkaloids are also summarized. All these studies indicate the lead potential of indolizidine alkaloids that in turn could be effective for future drug discovery.

The continuous attempt of drug discovery and search for a potential drug molecules with promising pharmacological activities is always of immense interest. Most of those chemical compounds having active pharmacological effects contain heterocyclic nucleus or compounds. Heterocyclic compounds clutch a particular place among pharmaceutically active natural and synthetic compounds. The ability to serve both as biomimetics and reactive pharmacophores of the heterocyclic nucleus is incredible and principally contributed to their unique value as traditional key elements of many drugs. These heterocyclic nuclei offer a huge area for new lead molecules in drug discovery and for the generation of activity relationships with biological targets to enhance their pharmacological effects. In the heterocyclic nucleus, the hydrogen bond acceptors and donors arranged in a manner of a semi-rigid skeleton in heterocyclic rings and therefore can present a varied display of significant pharmacophores. Lead identification and optimization of a probable drug target can be achieved by the generation of chemically diverse heterocyclic pharmacophores with different groups or substituents. Herein, an attempt is made to review and summarize the naturally occurring carbazole containing alkaloids obtained from Murraya, Causena and Glycosmis species and their potential towards anticancer activity. Carbazole is a tricyclic heterocyclic molecule and an integral part of naturally occurring alkaloids possessing various potential biological activities such as anticancer, antimicrobial and antiviral. Due to the high binding affinity of carbazole towards nucleic acid/ receptor and mimicking their biological activity, carbazole derived alkaloids exhibit the potential cytotoxic effect.

Quinoline and isoquinoline motifs are commonly encountered in natural products of diverse origins. These moderately basic fused-heterocyclic rings containing natural products are adorned with remarkable biological activities with clinical use in various diseases demonstrating nature elegance and creativity. Therefore, these privileged rings have attracted profound interest from the scientific community. In this perspective, we have discussed medicinal chemistry perspective of the natural products containing quinoline and isoquinoline scaffolds.

The deep Sea has several herbal sources such as marine organisms. These marine sources possibly have effective anticancer properties. The fused heterocyclic ring with marine source has special characteristics with minimum toxicity and with maximum anticancer effects. The review focused on and classified the prospective lead compounds which have shown a promising therapeutic range as anticancer agents in clinical and preclinical trials.

Humans experience different kinds of stress as a part of the day to day activity. The manifestation of stress will aggravate based on the physical conditions of individuals and due to their socio-economic situation of living. Herbal extracts have long been used in the traditional systems of medicine for the treatment of various ailments because of their potent antioxidant activity and lesser or no side-effects. Recently, there is a surge of interest toward the search of natural substances with diverse pharmacological activities, that can scavenge free radicals and protect cells from oxidative damage and apoptosis because of the adverse effects associated with the use of conventional medicines. Celastrus paniculatus is an endangered medicinal plant used for years in the traditional Ayurvedic system of medicine. The review presents the diverse chemical constituents of C. paniculatus and their pharmacological actions such as neuroprotective, memory-enhancing, anti-depressant, anxiolytic, anti-aging, hypolipidemic, anticancerous, analgesic, anti-inflammatory, antioxidant, anti-apoptotic, gastroprotective, anti-ulcerative properties at the cellular and molecular level based on the pre-clinical and clinical reports available. In the present review, we gathered the information from sources, such as Google Scholar, Science direct, PUBMED, and reviewed with a special focus on the mode of action of C. paniculatus at molecular biology from the data on animal and preclinical experiments to cure various ailments. These diverse medicinal values of C. paniculatus demonstrate its value as traditional medicine as a cure for multiple maladies.

Ethnopharmacological Relevance: Lannea microcarpa is an African herbal medicinal plant by pan-African distribution and has huge native medicinal and non-medicinal applications. The plant is being used traditionally as a medicine for many diseases such as mouth blisters, rheumatism, dysentery, sore throat, as a dressing on boils, as a cathartic, livestock feed, diarrhoea, gastroenteritis, malaria, dysentery, infection from bacteria, toothaches, gastroenteritis, female infertility, in blood pressure, oedema, coughing, cathartic, poisoning, and burns. It is also used in the manufacture of the cloths termed ‘basilan fini’ widely related to the concept of healing (medicine applied on cloth). Aim of the Review: This review aims to assemble an up-to-date review of the advancement made in the continuous pharmacological and phytochemical study of Lannea microcarpa and the consistent commercial and therapeutic application of it. These findings provide guide to the upcoming research on this plant. Methods: The assessment is systematically directed by searching the database of MEDLINE, PubMed, Springer, BMC, the Web of Knowledge, Google Scholar, ChemSpider and Science Direct for original research articles and books using related search terms. Results: Pharmacological studies verified the capability of this plant as it showed antioxidant, anti-inflammatory, and antibacterial activities. Bioactive constituents are found to be present in all parts of the plant. So far, this plant having high antioxidant capabilities, Lannea microcarpa is composed of many chemical compounds such as vitexin, lipids, proteins & amino acids, epi-catechin, gallic acid, myricetin, iso-Vitexin, fatty acid, carbohydrates, and tannins. This plant possesses antioxidant and antimicrobial properties owing to the presence of polyphenolics & flavonoids constituents. Novel compounds with the potent antiinflammatory effects such as 4’-methoxy-myricetin 3-O-α-L-rhamnopyranoside, myricetin 3-O-α-L-rhamnopyranoside, and myricetin 3-O-β-D-glucopyranoside among others, have been identified. Microparticles formulation of Lannea microcarpa was also prepared and further studies are still going on.

Background: Vitex negundo Linn. commonly known as five leave chase tree is an ethnobotanically important drug in traditional system of medicine. The plant is widely distributed in India, China and other Asian and American countries. Objective: The review aims at presenting comprehensive information with respect to ethnopharmacological relevance and recent findings on phytochemical and biological activities of Vitex negundo. Method: Literature was collected from various sources such as pubmed, scopus, science direct, and others. Results: Extracts and secondary metabolites of this plant, particularly those from roots and leaves, possess useful pharmacological activities such as anti-inflammatory, antitumor, antioxidant, antimicrobial, galactagogue, antigastric, antiflatulant, antiparasitic, analgesic, hepatoprotective and antihypertensive, some of which have been validated scientifically. All parts of the plant especially leave and roots contain a large number of bioactive phytoconstituents including flavonoids, iridoids, lignans, volatile oil, terpenes, coumarins, phenolic and steroidal compounds which impart multiple medicinal properties. Vitexin, isovitexin, viridifol, caffeic acid, chlorogenic acid and isochlorogenic acid are the main components. Conclusion: The review emphasizes the medicinal importance of Vitex negundo and its bioactive constituents in the traditional system of medicine.