Anti-nociceptive, anti-inflammatory and sedative activities of the extracts and chemical constituents of Diospyros lotus L.

Diospyros lotus L. is traditionally used in various diseases including pain and sleep disorders. The pain and inflammation are the common problems, which are treated with various synthetic analgesic drugs, and associated the side effects. The natural products have gained significant importance over synthetic drugs. The importance of phyto-medicine the current study has been designed with the aim to investigate the analgesic and anti-inflammatory effects of Diospyros lotus and bioassay guided isolation from its crude fractions. Seven known compounds; lupeol (1), 7-methyljuglone (2), β-Sitosterol (3), stigmasterol (4) betulinic acid (5), diospyrin (6; DS) and 8-hydroxyisodiospyrin (7; HDS) which were hitherto unreported from D. lotus. The chloroform fraction (CFDL) and isolated compounds DS and HDS were evaluated for anti-nociceptive, sedative and anti-inflammatory effects. The acetic acid induced writing was significantly (p<0.001) protected by CFDL (72.43%), DS (40.87%) and HDS (65.76%) at higher doses which exhibited peripheral and central analgesic effects in acetic acid and hot-plat pain paradigms. Regarding the anti-inflammatory effect the CFDL (77.43%), DS (80.54%) and HDS (75.87%) protected the carrageenan paw edema after 3rd h. The central analgesic effect was significantly antagonized with naloxone (0.5 mg/kg), showing opiodergic mechanism of action. The CFDL, DS and HDS were also proved sedative in open field animal models. In acute toxicity study the chloroform fraction [CFDL (50, 100 and 150 mg/kg)], DS (5 and 10 mg/kg) and HDS (5 and 10 mg/kg) were found safe. Our study concluded that CFDL, DS and HDS have marked anti-nociceptive, anti-inflammatory and sedative effect. The anti-nociceptive and anti-inflammatory effects of the roots of D. lotus are partially attributed due to the presence of analgesic constituents like diospyrin (DS), 8-hydroxyisodiospyrin (HDS) and strongly supports the ethno-pharmacological uses of D. lotus as anti-nociceptive, anti-inflammatory and sedative.