14.6 Conclusion and Future Perspective
Alstonia genus consists of many related species, and traditional usage of these
species highlighted the potential of such plants in exhibiting various pharmacological activities. Although many reviews are available on Alstonia species, the
present chapter is mainly focused on the pharmaceutical applications of the secondary metabolites from Alstonia genus. A preliminary literature review indicated
that more than 800 phytochemicals have been identified/isolated from the Alstonia
species, and these studies were reported mainly from China, India, Malaysia, South
Africa, etc., wherein a strong ethnomedical usage of these species have took place.
Further, in African Pharmacopoeia, A. boonei was listed as an antimalarial drug.
The majority of reported studies is mainly relying on the crude extract; however, the
present chapter dealt with the pharmacological application of the isolated phytochemicals from the Alstonia genus. To the best of our knowledge, around 32
species of Alstonia have been undergone the isolation process. However, 15
species-derived phytochemicals are only evaluated for the various pharmacological
activities. Among the vast isolated/identified phytochemicals, a few numbers (approx. 400) have been evaluated for a limited number of pharmacological activities.
In that scenario also, all the species-derived phytochemicals did not evaluate all the
reported activities. Especially, the search for potent pharmacologically active
phytochemicals from the A. scholaris is increasing in a dramatic manner, remaining
species are getting a negligible focus for their diverse activity. Evaluation of a
species correlated pharmacological activities might be helpful for the development
of a proper structural activity relationship of these compounds with respect to the
individual pharmacological activity as well as the species. Moreover, it will also
help to explore the structural similarities and their required modification for the
desired pharmacological activity. Monoterpenoid indole alkaloids are the major
components explored from the Alstonia genus and were exhaustively evaluated for
various pharmacological activities such as anti-cancer, antiviral, anti-spasmodic,
antitussive, antiarthritic, and antioxidant. Apart from that it also comprises iridoids,
flavonoids, steroids, fatty acids, etc.
Among the isolated phytochemicals, a varying degree of pharmacological
activities was observed. For instance, 2, 12, and 19 selectively inhibited COX-II.
Further, 67 against GSC-12# and GSC-18# exhibited a significant cytotoxicity.
Apart from that 27 exhibited a good in vitro antiviral activity similar to that of
acyclovir but lacked the selectivity. All these data have suggested that a proper
synthetic modification, either via chemical modification or by selecting the active
pharmacophore, might also result in the development of various novel drugs.
Although Alstonia-derived phytochemicals exhibited numerous activity, the
pharmacokinetic effects of these compounds are unexplored. A few studies are only
reported for the pharmacokinetics effects that mainly include 24, 75, 30, and 20.
The lack of pharmacokinetic studies might be taken care of by the scientific world
and will be helpful for obtaining a further exploration of the Alstonia genus.
528
A. T. Paul et al.
Alstonia genus consists of many related species, and traditional usage of these
species highlighted the potential of such plants in exhibiting various pharmacological activities. Although many reviews are available on Alstonia species, the
present chapter is mainly focused on the pharmaceutical applications of the secondary metabolites from Alstonia genus. A preliminary literature review indicated
that more than 800 phytochemicals have been identified/isolated from the Alstonia
species, and these studies were reported mainly from China, India, Malaysia, South
Africa, etc., wherein a strong ethnomedical usage of these species have took place.
Further, in African Pharmacopoeia, A. boonei was listed as an antimalarial drug.
The majority of reported studies is mainly relying on the crude extract; however, the
present chapter dealt with the pharmacological application of the isolated phytochemicals from the Alstonia genus. To the best of our knowledge, around 32
species of Alstonia have been undergone the isolation process. However, 15
species-derived phytochemicals are only evaluated for the various pharmacological
activities. Among the vast isolated/identified phytochemicals, a few numbers (approx. 400) have been evaluated for a limited number of pharmacological activities.
In that scenario also, all the species-derived phytochemicals did not evaluate all the
reported activities. Especially, the search for potent pharmacologically active
phytochemicals from the A. scholaris is increasing in a dramatic manner, remaining
species are getting a negligible focus for their diverse activity. Evaluation of a
species correlated pharmacological activities might be helpful for the development
of a proper structural activity relationship of these compounds with respect to the
individual pharmacological activity as well as the species. Moreover, it will also
help to explore the structural similarities and their required modification for the
desired pharmacological activity. Monoterpenoid indole alkaloids are the major
components explored from the Alstonia genus and were exhaustively evaluated for
various pharmacological activities such as anti-cancer, antiviral, anti-spasmodic,
antitussive, antiarthritic, and antioxidant. Apart from that it also comprises iridoids,
flavonoids, steroids, fatty acids, etc.
Among the isolated phytochemicals, a varying degree of pharmacological
activities was observed. For instance, 2, 12, and 19 selectively inhibited COX-II.
Further, 67 against GSC-12# and GSC-18# exhibited a significant cytotoxicity.
Apart from that 27 exhibited a good in vitro antiviral activity similar to that of
acyclovir but lacked the selectivity. All these data have suggested that a proper
synthetic modification, either via chemical modification or by selecting the active
pharmacophore, might also result in the development of various novel drugs.
Although Alstonia-derived phytochemicals exhibited numerous activity, the
pharmacokinetic effects of these compounds are unexplored. A few studies are only
reported for the pharmacokinetics effects that mainly include 24, 75, 30, and 20.
The lack of pharmacokinetic studies might be taken care of by the scientific world
and will be helpful for obtaining a further exploration of the Alstonia genus.
528
A. T. Paul et al.