The pharmacological information of medicinal plants has immensely contributed to health care, and scientific studies have shown that the evaluation of traditionally used medicines may provide leads towards effective drug discovery. Knowledge of the medical concepts in traditional system of medicine and its practice has lead to true innovation in drug development. It is approximated that more than 9,500 plant species are used for their therapeutic potentials (Narayana D.B.A et al., 1998). Moreover, FDA has even set up an exclusive department of complementary medicine to look for their role in health and diseases. Pterocarpus marsupium (PM) is one such plant that has been used for over thousands of years as a treatment of different diseases. It is used in 'Ayurveda' as 'Rasayana' for the management of various metabolic disorders. It has a long history of numerous traditional and ethnobotanical applications in diverse cultures. Many tribes considered it as a cure for all ailments. As per the traditional claim heartwood of Pterocarpus marsupium is the potential source of drugs used as an astringent, anti-inflammatory, anthelmintic, leprosy, skin diseases, diarrhea, asthma, bronchitis and grayness of hairs (Prajapati N.D. et al., 2000). It has been scientifically reported for hypolipidemic (Jahromi M.A. and Ray A.B., 1993), hepatoprotective (Mankani K.L. et al., 2005), anti-ulcer (Joshi M.C. et al., 2004), anti-inflammatory (Remsberg C.M. et al., 2008), and anti-diabetic activity (Karanjit N. et al., 2008). Extensive phytochemical studies have been carried out for this plant. Phytochemical testing showed that the methanol extract of P. marsupium contains carbohydrates, glycosides, saponins, tannins and flavonoids. The plant has been found to possess diverse number of biological activities. The P. marsupium tree has some medicinal property and is thus commercially exploitable. During the last five decades, apart from the chemistry of the P. marsupium compounds, considerable progress has been achieved regarding the biological activity and medicinal applications of P. marsupium. It is now considered as a valuable source of unique natural products for development of medicines against various diseases and for the development of industrial products. This review reveals the pharmacology of this valuable medicinal plant that ultimately provides the description, phytochemistry, and its activity in different medicinal ailments.

Pterocarpus marsupium Roxb. is a moderate to large deciduous tree, 30 meters high commonly found in hilly regions.It belongs to Family: Fabaceae, Subfamily: Faboideae, Tribe: Dalbergieae, Genus: Pterocarpus and Species: marsupium. It is called Bibla or Vijayasar/ Bijasar in Hindi and Indian Kino in English. It is native to India, Nepal, and Sri Lanka, where it occurs in parts of the Western Ghats in the Karnataka-Kerala region (Figure 1). It is also known by the names Malabar Kino, Benga, Bijiayasal (in western Nepal), Piasal (Oriya), Venkai, and many others. Its bark is brownish-grey, coming off in flakes, rough, longitudinally fissured and scaly, blaze pink with whitish marking (Mankani K.L. et al., 2005). Leaves are abundant, alternate without stipules, unequally pinnate with round petioles.

Figure 1 Geo-Distribution Map for Pterocarpus marsupium ROXB. in India (Ved D.K. et al., 2002-2004)

Extensive phytochemical studies have been carried out on the trunk and other parts especially the bark of this tree because of its medicinal value. Preliminary phytochemical screening of P. marsupium extract was done to test the presence of the active chemical constituents such as alkaloids, flavonoids, tannins, phenolic compounds, saponins, fixed oils and fats (Khandelwa K.R., 2004). Moreover, a variety of flavonoids and their derivatives have been isolated from various parts of the plant. It is also a rich source of polyphenolic compounds (Mayura R., 2004). Epicatechin (Figure 2) (Mol. formula-C₁₅H₁₄O₆), a flavonoid isolated from bark (Akhtar Hussain., 2004) is assumed to be the main compound responsible for anti-diabetic effect (Ahmad F et al., 1989). However, recently three important phenolic constituents from the heartwood of P marsupium extracted are; marsupsin (Figure 3), pterosupin (Figure 4), and pterostilbene (Figure 5). Marsupsin and pterostilbene significantly lowered the blood glucose level of hyperglycemic rats (Manickam M et al., 1997). Rastogi and Mehrotra (1982) isolated 5, 7, 2-4 tetrahydroxyisoflavone 6-6 glucoside, which is a potent antioxidant and believed to prevent cardio vascular diseases. Some other compounds like Stilbene, pterostilbene (Mathew J et al., 1997), β-eudesmol, triterpene alcohol, erythrodiol-3-monoacetate (Adinarayana, D et al., 1982), catechin, epicatechin (Chakravarthy B.K et al., 1981) (Figure 2), pseudobaptigenin, liquiritigenin, garbanzol, 5-deoxykaempferol, chalcone, isoliquiritigenin, dihydrochalcone, pterosuprin and aromatic aldehyde, p-hydroxybenzaldehyde (Adinarayana, D. and Syamasundar, K.V., 1982), marsupol (4,4` dihydroxy-L-methylhydrobenzoin) (Subba Rao et al., 1982), and pterocarpols A and B (Bhargava P.N. 1946), also had known medicinal values. It consists of 4,6,4-trihydroxyaurone-6-O-rhamnopyranoside (I) and 4,6,4-trihydroxy-7-methylaurone-4-O-rhamnopyranoside (II) (Mohan P. and Joshi T, 1989), Kinotannic acid (70-80%) (Dr. Nadkarni’s, 2002). Recently eight compounds have been detected in ethanol extracts of Pterocarpus marsupium wood and bark respectively (Maruthupandian A. and MohanV.R., 2011). The compounds of the Pterocarpus marsupium wood extract were found to be 3-O-Methyl-d-glucose (73.31%), n-Hexadecanoic acid (9.19%), 1, 2-Benzenedicarboxylic acid, di Iso octyl ester (7.56%), Tetradecanoic acid (3.47%) and 9, 12-Octadecadienoic acid (z, z)-(2.49%). However they found that in its bark, D-Friedoolean-14-en-3-one (40.29%) was the predominant constituent followed by Lupeol (33.24%), 3-0 Methyl-d-glucose (10.97%), 1, 2-Benzene - dicarboxylic acid, di-iso-ortyl ester (6.96%), n- Hexadecanoic acid (4.42%) and 9, 12-octadecedienoic acid (z,z)-(3.03%).

Figure 2 Epicatechin

Figure 3 Marsupsin

Figure 4 Pterosupin

Figure 5 Pterostilbene

3 Pharamacological profile of Pterocarpus marsupium

Warrier P.K., Nambiar V.P.K., Ramankutty C., 1995, In: Indian Medicinal Plants. Orient Longman Limited, Madras, 381-383