The key objective of this review is to emphasize on the usage of traditional wisdom in selection of candidate species as against random screening or on the basis of ethnomedicinal records. The author has reviewed few published studies and classical Ayurvedic literature for anticancer drug plants as the major source for drug discovery. Basis Ayurvedic wisdom, it is possible to apply the traditional knowledge on various herbs to identify the better leads for research and development to find out good anticancer drugs. Three disease conditions described in classical Ayurvedic texts have possible correlations to the description of cancer in modern medicine, viz. Arbuda, Granthi, and Gulma. These classical descriptions in terms of etiopathogenesis, symptoms, and prognosis related to these conditions go close to the cancerous conditions in modern context. Hence, it would be logical to assume that the botanical medicines recommended for use in these three conditions would have greater potential of hit rates in drug discovery program.
The author tried to identify the herbs from the authentic classical text, Bhavprakash
] traditionally employed in the treatment of cancer, and to analyze the same in terms of Rasa
(physico-chemical and pharmacodynamic properties), Veerya
(action after digestion and assimilative transformation), and Dosha Karma
(actions of Doshas
/humors). Based on this review, it has been possible to enumerate 53 herbs having acclaimed effects on Arbuda
, and Gulma
. The botanical identity for three of these 53 candidates could not be established. Therefore, the rest of 50 herbs are enumerated in .
Properties (karma) of herbs based on Ayurvedic principles
Further, these selected herbs were studied for their Ayurvedic pharmacological attributes, e.g. Rasa, Guna, Veerya, Vipaka, and Dosha Karma, as per the descriptions in Ayurvedic texts. The frequency analysis of the pharmacological attributes among these 50 herbs is provided in Tables –.
Analysis of herbs’ basis Rasa
Analysis of herbs’ basis Dosha Karma
Analysis of herbs’ basis Guna
Analysis of herbs’ basis Vipaka
Analysis of herbs’ basis Veerya
On the basis of the classical attributes for the herbs having Arbudahara/Gulmaghna/Granthihara effects, it can be safely assumed that these herbs share some specific pharmacological traits in common. Going by the dominance analysis of these attributes and mapping of their percentage distribution, the following scenario emerges.
Predominant Rasa: Tikta and Katu
Predominant Guna: Laghu, Ruksha, and Tikshna
Predominant Vipaka: Katu
Predominant Veerya: Ushna
Predominant Dosha Karma: Kapha-Vata Shamana.
Going by Ayurvedic pharmacological concepts, an anticancer drug tends to exhibit Tikta–Katu Rasa, Laghu–Ruksha–Teekshna Gunas, Katu Vipaka, and Ushna Veerya. They are generally Kapha–Vatashamak in terms of their Dosha Karma. With a view to enhance the scope of potential anticancer species, further screening of Bhavaprakasha Nighantu was carried out. The scope of this review was to enumerate other drugs having these specific pharmacological attributes but not listed under the Gulmahara/Granthihara/Arbudhnashak Karma properties. This round of review led to enumeration of 13 more botanical species which possibly have a potential for anticancer activity. These species are: Trachyspermum ammi, Nigella sativa, Juniperus communis, Mallotus philippinensis, Commiphora wightii, Calotropis procera, Calotropis gigantea, Moringa oleifera, Citrullus colocynthis, Cassia angustifolia, Luffa echinata, Amorphophallus campanulatus, and Tephrosia purpurea.
A schematic representation of this entire review process is shown in .
Process for selection of potential herbs on the basis of Ayurvedic wisdom
The above scheme of review of classical Ayurvedic Nighantus was taken up to identify and shortlist potential anticancer candidates with a presumption that such methodology would enhance overall hit rate during the screening phase.
The above-mentioned approach of the author is substantiated by a similar type of study conducted earlier by Smit et al
] who tried to identify the potential plant candidates for their cytostatic activity. The investigators worked to identify the candidate species on the basis of Samprapti
(pathogenesis) of the disease. In this process, they zeroed down to the herbs having Pitta Vardhak, Kapha Shamak
effects and Laghu, Ruksha
, and Tikshna Gunas
as their Ayurvedic attributes. In all, the investigators enlisted 44 species of which 14 candidates (Acorus calamus, Calotropis procera, Curcuma zedoaria, Datura metel, Mallotus philippinensis, Melia azedarach, Moringa oleifera, Plumbago zeylanica, Scindapsus officinalis, Semecarpus anacardium, Solanum indicum, Solanum xanthocarpum, Sphaeranthus indicus
, and Vitex negundo
) were screened against COLO 320 tumor cells, using cisplatin as control. It was observed in the study that seven species exhibited growth inhibition ranging between 83 and 100%.
Interestingly, three species, viz. Calotropis procera, Mallotus philippinensis, and Moringa oleifera find place in both the lists of anticancer herbs enumerated by Smit et al. and by the author. Two of these three common candidates (Calotropis procera and Mallotus philippinensis) exhibited cytostatic activity as reported by Smit et al. Such commonality of species indicates that it is possible to identify and shortlist the potential candidates for research purposes using the approaches having either a disease orientation (pathophysiological foundations) or drug orientation (pharmacological foundations). The concept can be relied upon from both these perspectives of Ayurveda.
This approach gets further validated by few published reports on anticancer activity of the botanical species shortlisted through the review mechanism being suggested by the author.
As seen from the study by Smit et al. and the reports enlisted in , the hit rates in biological screening tend to improve with selection of candidates on the basis of Ayurvedic tenets of pharmacology. If this approach is widely accepted and practiced, newer horizons would open for the development of potent Ayurvedic formulations in addition to the improved success rate in development of new drugs.
Published anticancer activity of the some of the shortlisted herbs