About Authors:
*Virendra Sharma, Pooja Sinoriya, Sunil Sharma
Lakshmi Narain Academy of Pharmacy, Gwalior

To evaluate the anti-inflammatory and analgesic activity of methanolic extract of whole plant of Sida acuta in experimental animal models. Methanolic extract of whole plant of Sida acuta (MESA) (100, 200 and 400 mg/kg p.o.) was studied for its anti-inflammatory activity using Carrageenan induced rat paw edema animal model and analgesic activity at the same dose level using acetic acid induced writhing test and Hot plate analgesia in mice. The methanolic extract of whole plant of Sida acuta (MESA) (100, 200 and 400 mg/kg p.o.). The PI with indomethacin and Sida acuta in carrageenan induced paw edema  at the dose level 400 mg/kg were 60% and 52.5% at the end of 5 hr. In the acetic acid induced writhing test, the extract at the dose level 400 mg/kg showed 83.78% inhibition of writhing. In radiant heat tail- flick method the extract  at the dose 400 mg/kg showed reaction time 4.902 ± 0.545 (p<0.001). The methanolic extract possesses anti-inflammatory and analgesic activity.

Reference Id: PHARMATUTOR-ART-1396

Inflammation is a local response of living mammalian tissues to injury. It is a body defense reaction in order to eliminate or limit the spread of injurious agent. There are various components to an inflammatory reaction that can contribute to the associated symptoms and tissue injury. Edema formation, leukocyte infilteration and granuloma formation represent such components of inflammation.[1] Aging is also considered to be inflammatory response. There are several tissue factors or mechanisms that are known to be involved in the inflammatory reactions such as release of histamine, bradykinin and prostaglandins.[2] Currently available anti-inflammatory agents are associated with unwanted side effects and have their own limitations. About 34-46% of the users of NSAIDs usually sustain some gastrointestinal damage due to the inhibition of the protective cyclo-oxygenase enzyme in gastric mucosa.[3] Therefore, new anti-inflammatory and analgesic drugs lacking these side effects are being researched as alternatives to NSAID and opiates. Attention is being focused on the investigation of the efficacy of plant based drugs used in the traditional medicine because they are cheap, have little side effects and according to WHO, about 80% of the world population still rely mainly on herbal remedies.[4,5,6]  

Sida acuta Burm (family- Malvaceae) is a small herb which is widely distributed in hotter parts of India. The Plant is native to Mexico and Central America but has spread throughout the tropics and subtropics.[7] It is used in alternative system of medicine as bitter tonic, diuretic, in nervous and urinary diseases, disorders of bile, chronic bowel complaints and in the rheumatic affections. It is also used in the treatment of intestinal worms, cures fever and headache.[8, 9, 10, 11] Several phytochemical screenings resulted in the isolation of various compounds from the plant involving alkaloids and steroidal compounds.[12] The main alkaloids are cryptolepineand its derivatives such as quindoline, quindolinone, cryptolepinone and 11-methoxy-quindoline. The major steroids of the plant are ecdysterone, beta-sitosterol, stigmasterol, ampesterol. Phenolic compounds such as evofolin A and B, scopoletin, vomifoliol, loliolid and 4-Ketopinoresinol have been isolated.[13] The plant is reported to have antifertility activity[14], antibacterial activity [15], anti-inflammatory, hepatoprotective activity [16], traditional healing for snakebites [17] and antihepatotoxic actions.[18] The present study was undertaken to evaluate anti-inflammatory and analgesic activity of methanolic extract of whole plant of S. acuta (MESA).

Materials and Methods
Plant Material

The selected plant were collected from Jorasi and Malanpur village Dist. Gwalior and were identified and authenticated by Mr. N.K. Pandey, Research officer (Botany) at Central Research Institute, Gwalior.

Drugs and Chemicals
All standard chemicals used in this study were of analytical grade. Indomethacin and carrageenan were obtained from Sigma-Aldrich, Germany. Acetic acid was obtained from Merck, Germany.

Preparation of extract
The collected plants were air-dried at room temperature, pulverized by a mechanical grinder sieved through 40 mesh. The powered materials (approx. 150 gm) were extracted with ethanol using soxhlet extraction apparatus. This ethanolic extract was then extraction apparatus and dried under reduced pressure. The extractive yield was found to be 13.02%. The ethanol free semi solid mass thus obtained was used for the experiment.[19]

Albino Wistar rats of either sex weighing 220-280 g and Swiss albino mice weighing 25-30 g were used for the assessment of pharmacological evaluation of methanolic extract of Sida acuta and Sida rhombifolia wherever necessary. Animals were procured from Defense Research and Development Establishment, Gwalior and maintained at Central Animal Facility of the Department. They were maintained at standard environmental condition (Relative humidity 55-65%, room temperature 25±2°C and 12 h light/ dark cycle) and were fed standard pellet diet and water ad libitum. Each experimental group consisted of five animals, housed in separate cages. All experimental protocols were approved by Institutional Animal Ethical committee of the Institute (approved by CPCSEA Regd. No. 716/02/a/CPCSEA).

Acute oral toxicity study of extract
The limit test for acute toxicity was carried out at 2000 mg/kg oral dose of MESA and MESR in rats as per OECD 423 guidelines.[20] The rats were observed continuously for 2h for behavioral, neurological and autonomic profiles and, after a period of 24 and 72 h, for any lethality, moribund state or death.

Assessment of Anti-inflammatory activity Carrageenan induced paw oedema in rat
The animals were divided into five groups of five albino wistar rats each (n=5). Acute paw oedema (Acute inflammation) was induced by sub-plantar injection of 0.1 ml of 1% freshly prepared carrageenan suspension in normal saline into the right hind paw of each rat. The left hind paw was injected with same volume of 0.1% of normal saline. Rats were pretreated with Vehicle or MESA  or aspirin 1 hr before carrageenan administration. The paw size was measured in mm using Plethysmometer at 1st and 3rd h after carrageenan administration. The percent inhibition was calculated by following formula.

Percentage Inhibition = Vc - Vt / Vc *100

Where,   VC = Mean increase in paw volume in control group
Vt = Mean increase in paw volume in test group [21]



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