Pharmaceutical Application of Bio-actives from Alstonia Genus: Current Findings and Future Directions

Abstract

Genus Alstonia is comprised of around 155 species throughout the world. Phytochemical screening of Alstonia genus has demonstrated the presence of diverse phytochemicals that include at least 800 distinct metabolites. The main classes of metabolites are alkaloids, iridoids, flavonoids, fatty acids, etc. Secondary metabolites from this genus also bring positive results when employed as anticancer, anti-spasmodic, antitussive, antiarthritic, antioxidant, etc. Alstonia boonei is listed as an antimalarial drug in African pharmacopoeia. In China, a formulation consists of A. scholaris leaves-Dengtaiye tablets are used for the treatment of cough and fever symptoms. Recently, A. scholaris leaves-derived indole alkaloids have been registered as an investigational new botanical drug (No. 2011L01436) and China Food and Drug Administration (CFDA) has approved its phase I/II clinical trials for the treatment of respiratory diseases. Pharmacokinetic and safety analysis of this botanical drug in healthy human subjects have revealed a safe profile under the dose regimen experiment. Apart from that, strictamine, an indole alkaloid isolated from A. scholaris exhibited a similar in vitro antiviral activity to that of acyclovir. The present chapter is mainly focused on the critical analysis of various secondary metabolites isolated from Alstonia (approximately 15 species). Apart from that, pharmacological, toxicological and intellectual property rights studies have also been included.

Bisindole Alkaloids from the Alstonia Species: Recent Isolation, Bioactivity, Biosynthesis, and Synthesis

“…Alstonia , a major genus in the Apocynaceae family of plants, has nearly 155 species and is found all over the world [ 4 ]. Robert Brown named it in 1811 in honor of Charles Alston (1685–1760), an eminent botanist at the University of Edinburgh [ 4 ].…”

“…Alstonia , a major genus in the Apocynaceae family of plants, has nearly 155 species and is found all over the world [ 4 ]. Robert Brown named it in 1811 in honor of Charles Alston (1685–1760), an eminent botanist at the University of Edinburgh [ 4 ]. The Alstonia genus’ trees and shrubs are prevalent in the tropical and subtropical parts of Africa, Asia, and Australia [ 5 ].…”

“…The Alstonia genus’ trees and shrubs are prevalent in the tropical and subtropical parts of Africa, Asia, and Australia [ 5 ]. They contribute significant pharmacological activity, including anticancer, antileishmanial, antimalarial, antitussive, antiviral, antiarthritic, and antibacterial activities [ 4 , 5 , 6 , 7 , 8 , 9 ]. Several parts of the plants including bark, twigs, and leaves have been traditionally used to treat diseases.…”

“…Their useful biological activity has aroused profound interest, as indicated by the increasing number of publications and patents each year. To date, more than 300 patents have been filed under the Alstonia genus with various formulations [ 4 ]. Notably, 157 different monoterpenoid indole alkaloids have been isolated from this genus between 2010 to 2020 [ 10 ].…”

“…These natural products, along with flavonoids, fatty acids, etc., are the major classes of secondary metabolites that are believed to be parts of the plants’ defense mechanism. To date, many monoterpenoid indole and bisindole alkaloids have been found in the Alstonia genus [ 4 ]. Modern clinical application of many of these alkaloids are similar to their traditional or folklore applications; for example, cocaine and morphine were used as anesthetics while caffeine and nicotine were used as stimulants [ 12 ].…”