Frontiers in Natural Product Chemistry

It is believed that natural products exhibiting medicinal benefits do not cause systemic side effects or they cause acceptable side effects. Due to the increase in research output and increased awareness about the importance of natural products, nowadays, a large fraction of the population is now shifting their orientation towards the use of natural products in daily use. Turmeric (Curcuma longa) is one such blessing for all of us. It is one of the most important and abundant spices used in Asian food. It is cultivated around the world and originated in India, Indonesia, and Southeast Asia. Turmeric powder has a bitter, sharp taste and is yellow. It is used to provide color and flavor to various food products such as; butter, mustard, cheese, etc. Turmeric belongs to the Zingiberaceae family. It is one of the most commonly used medicinal herbs in India and China and is used for the treatment of jaundice and liver problems. Turmeric is known to have a wide range of pharmacological properties such as anti-microbial, anti-protozoal, anti-malarial, anti-venom, anti-proliferative, anti-aging, antiinflammatory, anti-tumor, etc. It is identified that the yellow color of the turmeric is due to the presence of Curcumin which is the most important and potent bioactive compound of turmeric. Curcumin is a curcuminoid that is extracted from the rhizomes of Curcuma Longa. Curcumin possesses remarkable medicinal properties and can also be used in cosmetic products. Curcumin has powerful anti-inflammatory and antioxidant properties. It helps to treat various diseases, some of them are; hay fever, depression, Alzheimer’s, treat cholesterol, itching, and osteoarthritis. It is involved in maintaining the functioning of the brain and reduces the risk of brain and heart diseases. Investigators are focusing to find out the therapeutic role of curcumin in asthma, diabetes, cancer, indigestion, and many other disorders. In this chapter, we will discuss the natural compounds present in turmeric and their medicinal importance.

Due to the increase in cancer cases nowadays, an increase in studies related to treatment has been observed. Although many natural or synthetic compounds have been described as therapeutic today, the effects of these treatments are seen in both healthy and cancer cells. In order to reduce these undesirable effects seen in chemotherapy and radiotherapy, alternative treatments that have less effect on healthy cells or alternative attitudes that will allow the minimum use of therapeutics in these treatments continue to be investigated. In particular, such studies focus on natural compounds with phenolic properties. This chapter focuses on the relationship between coumarin derivatives, curcumin, Olea europaea leaf extract, and Cynara scolymus leaf extract with hepatocellular carcinoma. Furthermore, the effect of these natural compounds on the genetic hallmarks of various signalling pathways and important cellular metabolism molecules of hepatocellular carcinoma are discussed.

Dwindling of natural resources coupled with the rising demand for several botanical ingredients in the Indian subcontinent and global market has led to scarcity and extensive adulteration. This may result in altered safety and efficacy of several single and polyherbal Ayurvedic formulations. Foreseeing this, Ayurveda experts have decided to use alternate herbal ingredients with similar properties. Such ingredients are known as Pratinidhi (a substitute) and are used in medicinal preparations. Because of the unavailability of a particular herb or the availability of the herb at a prohibitive cost, the usage of substitutes is necessary. This concept of substitution of herbs in Ayurvedic medicines is quite an elaborate and popular practice. In commerce, there are some predominant herbs whose substitutes or adulterants are also being traded. These substitutes belong to the same or different genera or cultivar species and may or may not have similar phytochemical constituents. This also relates to the use mentioned in the authoritative texts of Ayurveda and their modern pharmacological responses and safety. Ayurvedic system of medicine has an in-depth biochemical classification of herbs, based on which substitutes can be deduced. In addition, ancient texts have mentioned alternate herbs for some key ingredients. In the present article, we are discussing commercially significant herbs, viz. Ativisha, Bala, Guduchi and Vidanga. These herbs have diverse clinical usage in Ayurveda and are reported to have properties such as immunomodulatory, anti-pyretic, anti-oxidant and anthelmintic. Based on this concept, the development of standard protocols for highly traded botanical ingredients will help the healthcare industry to meet the quality standards for medicinal products. Using substitute herbs will majorly reduce the overexploitation of natural resources and help bring balance to the ecosystem.

A biofilm is a form of bacterial cluster normally seen in environmental niches. They are immobile communities that colonize and develop on medical implants like sutures, catheters and dental implants, which can be treated only by their removal, leading to unaffordable treatment. The main biofilm consequence is its increased tolerance to negative environmental conditions, which includes resistance to antibiotics and antimicrobial agents. The high resistance of bacterial biofilm towards external stress and antibiotics is due to the extracellular polymeric matrix, which provides a barrier from the external environment. The biofilm development is facilitated by the cell-to-cell communication mechanism of bacteria called quorum sensing, which promotes the bacterial community to mature. There is a huge number of naturally occurring chemical compounds that can act as antibiofilm agents. Different chemical compounds resist bacterial biofilm growth by different mechanisms depending on the chemical structure of the molecule, and the stage of biofilm formation at which we introduce the chemical compound into the biofilm system. The anti-biofilm activity of a natural or synthetic compound mainly depends on certain aspects; some of them will deal with the inhibition of the formation of the polymer matrix, some others may suppress the cell adhesion and its attachment to itself or an external surface, while others deal with the interruption of extracellular polymeric matrix generation and lessening virulence factors production, thereby hindering QS network and biofilm development.

Natural products are investigated for their remunerative effects on health. Quercetin, a flavonoid, is commonly distributed in vegetables and fruits. Quercetin is used as a supplement in food and as a phytochemical remedy against several diseases, including circulatory dysfunction, neurodegeneration, diabetes, cancer, and inflammation. The most prominent property of quercetin is its antioxidant activity, enabling it to douse free radicals. Derivatives of quercetin are essential metabolites, and even various conjugates are being advocated by the Food and Drug Administration (FDA) for use in humans. So, the biosynthesis of quercetin derivatives is a predominant field of research. Methylation and glycosylation are two essential strategies used to synthesize various metabolites of quercetin that do not exist in nature. This review summmarizes quercetin chemistry, structural modifications, Structure-Activity Relationship (SAR) studies, and therapeutic applications of quercetin.