Neuroprotective Effects of Protocatechuic Acid in Diabetes Induced Neuropathic Pain

Unani Formulation Habb-e-Suranjan: A Treasure of Biological Activities

Habb-e-Suranjan (HES), an Unani formulation, has been studied for its anti-inflammatory properties in both in vitro and in vivo experiments. HES is recommended for arthritis, gout, and joint pain. The current endeavor is an attempt to put it to the test and verify its efficacy scientifically. It was tested for DPPH, hydroxyl, and nitric oxide scavenging activities. It was shown that HES had the greatest TAC and FRAC values when compared to catechin and ascorbic acid. HES exhibited DPPH and hydroxyl radical scavenging activity that was dose-dependent. Incubation of sodium nitroprusside solutions in PBS at 25°C for 150 min resulted in the production of nitric oxide. Nitric oxide production was effectively decreased by HES. Anti-inflammatory medications boosted the migration of PMN cells toward the chemoattractant FMLP in an agarose experiment of PMN chemotaxis. In carrageenan-induced rat paw edema, in the HES-treated group, paw thickness was 3.021 ± 0.084 at t = 0, but it showed an increase in paw inflammation after one hour, i.e., 3.195 ± 0.082 cm which again showed a decrease in paw thickness up to 4th hour, i.e., 3.018 ± 0.078, 2.98 ± 0.032, and 2.684 ± 0.061 at t = 2, 3, and 4, respectively. It showed again getting back to the normal thickness of paw at t = 24 hrs, i.e., 3.029 ± 0.118 cm. It is concluded that the formulation is potent enough and can be used effectively for the treatment of inflammation and associated health issues. Moreover, there is much scope to evaluate its effectiveness using different in vitro and in vivo models.

Antidiabetic and antioxidant activities: Is there any link between them?

An empirical relationship between antidiabetic and antioxidant properties of molecules using protocatechuic acid (PcA) as a test compound has been found.

The possible mechanisms of protocatechuic acid-induced central analgesia

It is aimed to investigate the central antinociceptive effect of protocatechuic acid and the involvement of stimulation of opioidergic, serotonin 5-HT_2A/2C, α2-adrenergic and muscarinic receptors in protocatechuic acid-induced central analgesia in mice. Time-dependent antinociceptive effects of protocatechuic acid at the oral doses of 75, 150 and 300 mg/kg were tested in hot-plate (integrated supraspinal response) and tail-immersion (spinal reflex) tests in mice. To investigate the mechanisms of action; the mice administered 300 mg/kg protocatechuic acid (p.o.) were pre-treated with non-specific opioid antagonist naloxone (5 mg/kg, i.p.), serotonin 5-HT_2A/2C receptor antagonist ketanserin (1 mg/kg, i.p.), α2-adrenoceptor antagonist yohimbine (1 mg/kg, i.p.) and non-specific muscarinic antagonist atropine (5 mg/kg, i.p.), respectively. The antinociceptive effect of protocatechuic acid was observed at the doses of 75, 150 and 300 mg/kg in tail-immersion test, at the doses of 150 and 300 mg/kg in hot-plate test at different time interval. The enhancement in the latency of protocatechuic acid-induced response to thermal stimuli was antagonized by yohimbine, naloxone and atropine in tail-immersion test, while it was antagonized only by yohimbine and naloxone pretreatments in hot-plate test. These results indicated that protocatechuic acid has the central antinociceptive action that is probably organized by spinal mediated cholinergic and opiodiergic, also spinal and supraspinal mediated noradrenergic modulation. However, further studies are required to understand how protocatechuic acid organizes the interactions of these modulatory systems. As a whole, these findings reinforce that protocatechuic acid is a potential agent that might be used for pain relief. Additionally, the clarification of the effect and mechanisms of action of protocatechuic acid will contribute to new therapeutic approaches and provide guidance for new drug development studies.