Discovery of resins in Pleurolobus gangeticus ( Desmodium gangeticum) roots, need for good anatomical studies in Pharmacognosy.
4th Oct., 2022, Vadodara
When we study pharmacognosy of any root or stem in our lab. we used to take longitudinal sections (both TLS and RLS) to find out the dimensions of vessel segments and the nature of pitting, as well as the nature (shape and inclusions) of medullary rays (both in xylem and phloem) to get a complete picture of vascular architecture of the material. During a study on the roots of Pleurolobus gangeticus (L.) J.ST._ HIL (Desmodium gangeticum DC), one of the “Dasamoola”, we observed hard yellowish resinous material filling many of the vessel segments as well as yellow liquid resin in some others. In mature vessels these resins appeared granular. Masses of resins were observed in root powder also. This led to analysis of root resins of this plant and it’s active components.
The resin from roots were extracted in methanol and water soluble separated. Since the water fraction was turbid, it was the extracted with ethyl acetate to get resin rich fraction. This was then analysed using LCMS. Of the large number of compounds located in the resin in LCMS analysis, only 48% consisting of 12 compounds are identified. Among 12, only 3, i.e. diisobutyl phthalate (C16H22 O4-)18%; 3α,12α-dihydroxy-5β-chol-8(14)-en-24-oic Acid (C24 H38 O46) 11% and 8α-Seco-6,8α-deoxy-5-oxoavermectin (C34 H50 O8) 8%,are present in appreciable quantities and these 3 amounted to 37% of the resin. The minor compounds which occur at concentrations between O.5 -1% are nine in number. They are gingerdione; (C17H24O4), amphibine H (C33H43N5O6), alverine (C20 H27 N); trans-1,2-diphenylcyclobutane (C16H16) acetyleugenol (C12H14 O3), acetyl tributyl citrate (C20 H34 O8), cinncassiol D3 (C20 H32O6), 2-alpha-methyl-17beta-[(tetrahydro-2H-pyran-2-yl)oxy]-5alpha-androstan-3-one ( C25 H40 O3) and deoxymiroestrol (C20 H22O5). There were three major and five minor unidentified components, all together totalling to 52% of the resin.
Almost all the compounds in resin, which are identified, possess distinct medicinal properties such as anticancer, antidiabetic, cardiotonic and antimicrobial properties. Diisobutyl phthalate, which the major component in resin (18%), is a PPAR modulator which hold great potential for the management of cancer patients by acting as critical sensors and regulators of lipid. It is able to promote eNOS activation, regulate immunity and inflammation response, and affect proliferation and differentiation of cancer cells[3]. The second major compound (11%), 3α,12α-Dihydroxy-5β-chol-8(14)-en-24-oic Acid (C24 H38 O46), also known as apocholic acid, a bile acid and support liver function. Avermectins and its derivatives which amount to 8%, possess anticancer, anti-diabetic, antiviral, antifungal properties and are used for treatment of several metabolic disorders. They are anthelmintics also[4].Gingerdione is an excellent antioxidant. Amphibine H is an oligopeptide isolated first from Ziziphus spinachristi and Z. Xylopyrus. Alverine is a smooth muscle relaxant used to relieve cramps or spasms of the stomach and intestines. It is therefore useful in treating irritable bowel syndrome. Acetyl eugenol is similar to eugenol found in several plants such as Acacia nilotica and Piper betle and has identical antibacterial and antifungal properties. It is a potent platelet inhibitor and abolishes arachidonate (AA)-induced aggregation[5]. Acetyl tributyl citrate (ATBC) is a FDA-approved substance for use as a pharmaceutical excipient. It is used in pharmaceutical coating of solid oral dosage forms such as coated tablets or capsules. Miroestrol is a phytoestrogen, which mimics the biological activity of the hormone estrogen and is said to possess rejuvenating properties.
Since we could not identify the remaining 8 compounds we are unable to comment on their pharmacological action. But it is assumed that they possess similar or different medicinal properties.
The results explicitly prove the substantial and unique medicinal properties of the roots of Pleurolobus gangeticus which are used as a component of the “Dasamoola”. The absence of resin in other plant parts like leaves and stems reduces their medicinal values. The practice of using “Panchang” (all the aerial parts together) of this plant in place of roots in Dasamoola preparations is not to be encouraged because the aerial parts are devoid of the resin (and its active pharmacological components) and the many healing properties of its chemical components. Adding the entire aerial parts of Pleurolobus gangeticus in medicinal preparations like “Dasamoolarishtam”, “Chyavanaprasam” and “Dhanvantharam” will result in substandard medicines and will reduce the credibility of these drugs which are highly sought after in Ayurveda. Similar results upholding the superiority of roots over the aerial plant parts, which are commonly used in Ayurvedic preparations, were already obtained in Tribulus terrestris and Solanum americanum, two other herbaceous components of Desamoola [6,7]
References
Mammen Daniel, Janvi Patel, Nishtha Patel and Dhwani Pathak (2022), LCMSanalysis of root resins of Pleurolobus gangeticus (L.) J.ST._ Hil. (syn. Desmodium gangeticum (L.)DC. WJPPS. 11(10); 1941-1946
Mammen Daniel
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