Biological activities of hydroxyanthracene derivatives (HADs) from Aloe species and their potential uses

Abstract

Hydroxyanthracene derivatives (HADs) are a class of naturally occurring organic compounds known for their diverse biological activities and applications. Due to their pharmacological versatility, hydroxyanthracene derivatives represent a major area of interest in natural products research and drug development. They are found in a wide variety of organisms including bacteria, fungi, plants and some animals. One of the most important sources of HADs is the plant Aloe vera, which is particularly rich in these compounds. HADs can be divided into several types based on their chemical structure and the presence of functional groups: anthraquinones, anthrones, anthranols, anthracenols and dianthrones, with anthraquinones being the most abundant. Plants are a particularly rich source, with around 200 known anthraquinones found in roots, rhizomes, flowers and fruits. These compounds are known for their diverse biological activities, including anticancer, anti-inflammatory, diuretic, antiarthritic, antifungal, antibacterial and antimalarial properties. Some anthraquinones are already in clinical use and commercially available. In addition to their medicinal applications, these molecules are valuable in analytical chemistry and industrial processes such as cellulose production, and serve as dyes, agrochemicals and prototypes for the development of new bioactive molecules. Various techniques are used to extract anthraquinones from natural sources to maximize yield and preserve the integrity of the compounds. Common methods include maceration, soxhlet extraction, supercritical fluid extraction, green processes and ultrasound-assisted extraction. This chapter focuses on the key properties and applications of anthraquinone from Aloe vera. Through a comprehensive review of these aspects, this chapter aims to provide a thorough understanding of the potential of anthraquinones and their diverse roles in both natural and applied sciences.