Chemical composition of Microstylis wallichii Lindl. from Western Himalaya

Abstract

Microstylis wallichii Lindl. is a Rasayana and belongs to the “Astverga”. It is an important medicine traditionally known since Vedic period but study on its phytoconstituents is very limited. Metal content and volatile constituents in M. wallichii (family Orchidaceae) collected from Uttarakhand were analyzed by Atomic Absorption Spectrophotometer and GC and GC-MS respectively. Chemical analysis revealed that wild M. wallichii contained 6.48 ppm Cu, 43.00 ppm Zn, 35.00 ppm Mn, 331.00 ppm Fe, 21600.00 ppm K, 9000.00 ppm Ca, 2800.00 ppm Mg, 198.00 ppm Al, 26.70 ppm Ba, 55.60 ppm B, 0.30 ppm Mo, 156.00 ppm Cl.  Fatty acids analysis revealed the presence of the following constituents-linoleic acid (18:2ω6) 61.20% (w/w), α-linolenic acid 18.10% (w/w), oleic acid 12.00 % (w/w), palmitic acid (16:0) 6.00% (w/w), stearic acid (18:0) 2.10% (w/w), γ-linolenic acid (18:3ω6) 2.20% (w/w), eicosanoic acid (20:0) 0.81 % (w/w), eicosenoic acid (20:1) 0.42% (w/w) and eicosadienoic acid (20:2) 0.04% (w/w). Cultivated M. wallichii contained 7.18 ppm Cu, 49.50 ppm Zn, 37.00 ppm Mn, 352.45 ppm Fe, 23000.00 ppm K, 13000.00 ppm Ca, 5300.00 ppm Mg, 217.50 ppm Al, 37.50 ppm Ba, 59.70 ppm B, 0.27 ppm Mo, 148.00 ppm Cl. Analysis of fatty acids reported following constitutents of cultivated M. wallichii - linoleic acid (18:2ω6) 65.23% (w/w), α-linolenic acid 15.50% (w/w), oleic acid 14.87 % (w/w), palmitic acid (16:0) 5.90% (w/w), stearic acid (18:0) 2.50% (w/w), γ-linolenic acid (18:3ω6) 1.87% (w/w), eicosanoic acid (20:0) 0.69 % (w/w), eicosenoic acid (20:1) 0.52% (w/w) and eicosadienoic acid (20:2) 0.07% (w/w). Other chemical constituents which were isolated from wild and cultivated M. wallichii were vitamins α–tocopherol and γ-tocopherol 12.00-9.80 ppm and 695.00-786.7 ppm respectively while terpenoids 18.00-20.50%. It has an acid value of 1.20-1.39 and saponification value of 103.00-110.50.   Key words: Microstylis wallichii; metal content; volatile constituents; GC-MS