HPLC-MS/MS Profile, Analgesic and Anti-inflammatory Activities of Lawsonia inermis Seed Fractions

Pain and inflammation are common symptoms present in many medical conditions, typically managed with analgesic and anti-inflammatory medications. However, these medications, whether targeting peripheral or central pathways, are often associated with adverse side effects. This study aimed to identify the constituents of Lawsonia inermis seed fractions, and evaluate the analgesic, and anti-inflammatory activities of these fractions. Chemical constituents of the fractions were characterized using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The analgesic properties were evaluated using the acetic acid-induced writhing and tail immersion tests, while anti-inflammatory activity was assessed via the carrageenan-induced paw edema model in mice. A total of 29 compounds were identified, with the ethanol fraction exhibiting the highest concentration of the constituents, amounting to 93.89 mg/g fraction. Major compounds detected in the ethanol fraction included gallic acid, catechin, tannic acid, vanillin, epicatechin gallate, isoquercitrin, and ellagic acid. The study revealed that the ethanol fraction demonstrated a notable peripheral analgesic effect, achieving 34.75% inhibition at a dose of 250 mg/kg in mice, while the aqueous fraction showed substantial central analgesic activity in rats at 500 mg/kg throughout the experimental period. Additionally, at a dose of 400 mg/kg, the ethanol fraction resulted in a 74.05% inhibition of inflammation in mice, outperforming indomethacin, which achieved a 58.09% inhibition at 10 mg/kg after 4 h. These findings present novel evidence that the fractions of L. inermis seed exhibit significant analgesic and anti-inflammatory activities, supporting the traditional medicinal use of this plant for the management of conditions involving pain and inflammation.