Katuki ( Picrorhiza Kurroa ) -A promising Ayurvedic Herb

Through much of human history, plants have been the basis for medical treatments and such traditional medicine is still widely practiced today. [1] India and China are one of such countries who boost their traditional systems of medicines and the respective Govt. of these countries also takes required measures from time to time. According to an estimate made by the World Health Organisation (W.H.O.) traditional medicine forms the basis of primary healthcare of about 80% population of the world. Primary reason for that being the inexpensive nature of herbal medicines as compared to modern pharmaceutics as these can be grown from seed or gathered from nature for little or no cost. Katuki ( Picrorhiza kurroa Royle ex Benth) is a very popular hepatoprotective drug in Ayurvedic system of medicine. P. kurroa is mainly used for the treatment of hepatic disorders, but it is also known for its anti-inflammatory, anti-microbial, anti-diabetic, immunomodulator, anti-asthma and in the management of obesity. The most important of these bioactive compounds of plants are iridoids, cucurbitacin and acetophenones. The present review study is an attempt to provide reported detail information of this herb from various Samhitas and its study in modern area like its phytoconstituents and pharmacological activities.

in diameter. Other surface is grey or creamish brown in colour, bearing impressions of round root scars and numerous scales.
The rhizome terminates in scaly leaf, bud or stem. Fracture: short and clear Odour: faint or disagreeable Taste: very bitter and long standing ( Figure 1).

Phytochemical Properties
The major chemical constituents are D-mannitol, Kutkiol, Kutkisterol, apocyanin, phenol glucosides, androsim, and picein iridoid glycosides; kutkin, picroside I, II&III; Kutkoside, minecoside, picrorhizin, arveninIII. Kutkin is the active principle of P. kurroa and is comprised of kutkoside and the iridoid glycoside picrosides I, II, and III. Other active constituents are drosin, apocynin, and nine cucurbitacin glycosides whereas catechol -apocynin has been found active as an anti-inflammatory agent and cucurbitacins for antitumor and cytotoxic effects. Chemical studies on the rhizomes of P. kurroa revealed acetophenones, cucurbitacins and iridoids presence in them. As per literature there are several bioassays on the constituents isolated from the rhizomes focused on hepatoprotective, immune-modulating and antioxidant activities [31].

Pharmacological Actions
Hepatoprotective Activity: Katuki has been widely known and used as hepatoprotective agent. In liver injury mainly Kuffer cells cause problems in regeneration process and it here when extract of this plant plays its role by suppressing cells [4]. Picroliva iridoid glucoside compound [ mixture of Picroside-1 and Kutkoside (1.0: 1.5, w/w)] from rhizome and roots of this plant is prominently known to help in regeneration. This hepatoprotective activity of picroliv was studied in rats liver where hepatic injury was induced by ethanol [5]. This plant has been currently used in treating various liver diseases which includes fatty liver, viral hepatitis, ischemic injury, cirrhosis, radiation toxicity etc. Studies proved picroliv effective in hepatoprotective action against paracetamol, carbon tetrachloride, alcohol and aflatoxin Zhang, et al. [6].
Anti-Asthmatic Activity: Phenolic Glycoside named androsin is found prominently active in anti asthmatic effects. This glycoside activity in studied in guinea pigs where it inhibit allergen as well as Platelet-activating factor (PAF) induced obstruction in bronchia [7].
Inhibiting histamine release in chopped lungs of guinea pigs was also observed by exposing them to root powder of this plant [8].
Anticancer Activity: Picroliv, from Picrorhiza kurroa showed protective action against chemically induced tumour and C. albicans [30]. In another study by using agar well diffusion method they found ethanolic extract of rhizome showed high antibacterial activity in the range 10.3 to 16.16mm against S.aureus, B.cereus, E.coli, K.pneumoniae, S.typhi and S.pyogens whereas the methanolic extracts showed high antibacterial activity against S.aureus (12.1 ± 0.13mm) and P.aeruginosa (13.06 ± 0.15mm) Kumar, et al. [12]. According to the literature there are vast diversity of microbial flora in this plant termed as endophytes and current findings suggest that these endophytes might be responsible for all its medicinal properties. One such report by Raina, et al. [13] where they investigated antibacterial and antifungal activities of Picrorhiza kurroa harboring endophytes and they identified two bacterial endophytes i.e., which were effective against several human pathogens.
Anti-Inflammatory Activity: Picroliv is also known for antiinflammatory responses. Rhizome extracts was reported to be effective in a dose dependent manner in rats against carrageenaninduced paw edema and cotton pellet-induced granuloma formation [14]. Picroliv role was also studied for anti-inflammatory response in ulcerative colitis (UC) mice model which suggested that its administration could be a therapeutic approach [6]. Alcholic extract of kurroa and compounds kutkin, Picroside-1 and Kutkoside have been reported for their anti-inflammatory activity [15].

Anti-Diabetic Activity: Extract of this plant is providing
beneficial results in diabetes also. Study has demonstrated that its administration increased insulin production in rats which had Streptozotocin Evoked β-Cell Damage [18]. In vivo studies in rats suggested that its extract played potential role in type-2 diabetes induced by streptozotocin-nicotinamide [16].
Anti-Oxidant Activity: Ethanolic extract of rhizome has been reported in scavenging free radicals which ultimately can prevent many ailments in humans. It has also its role in diseases related oxidative stress and it can also be given as natural antioxidants supplement [17].
Immunomodulator Activity: Aqueous and ethanolic extracts of Picrorhiza kurroa have been reported for stimulating humora; responses by various immune mechanisms which includes mediators releasing in hypersensitivity as well as tissue responses at the target site organ of these mediators Sharma, et al. [29]. One of the Biopolymeric fraction from this plant RLJ-NE-205 also showed cell-mediated immune response by stimulating CD4+ and CD8+ T cells Gupta, et al. [19].

Conclusion
Katuki has been one of the important sources of Ayurvedic medicine as well as modern medicine. Although it's majorly used for liver disorders, but its active components present in various parts of plant are providing relief and saving millions of life from the very ancient time. Due to wide spectrum of biological activities this plant is widely used in drug industries. Iridoids present in it is also widely known for antitumor, choleretic, hypolipidemic, antiphosphodiesterase, cardioprotective, neuritogenic, molluscicidal and leishmanicidal activities [22]. This plant also contain sveron-icoside , phenol glycosides and pikuroside. Besides roots and rhizome leaf, stem and seeds are also a source of variety of components which makes this plant a remarkably promising herb [23][24][25][26][27][28][29].