Delta- and mu-opioid pathways are involved in the analgesic effect of Ocimum basilicum L in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Ocimum basilicum L. is a perennial herb that has been used in traditional Asian Indian medicine for thousands of years as a natural anti-inflammatory, antibiotic, diuretic, and analgesic. AIM OF THE STUDY: The present study was conducted to investigate the analgesic effects of basil essential oil (BEO) in inflammatory pain models and identify underlying mechanisms. We further investigated whether BEO affects physiological pain and motor coordination. MATERIALS AND METHODS: The analgesic effects of BEO were assessed in various mouse experimental pain models using formalin, acetic acid, heat, and carrageenan as stimuli. BEO was administered by intraperitoneal injection or inhalation. The involvement of various pathways in the analgesic effect of BEO was assessed by pretreating mice with selective pharmacological inhibitors, administered intraperitoneally. Opioid pathways were tested using the κ-opioid antagonist 5'-guanidinonaltrindole (GNTI; 0.3 mg/kg), δ-opioid antagonist naltrindole (NTD; 5 mg/kg) and µ-opioid antagonist naloxone (NAL; 8 mg/kg); nitric oxide (NO) pathways were tested using the NO synthase inhibitor N-nitro l-arginine methyl ester (L-NAME; 37.5 mg/kg) and NO precursor L-arginine (L-Arg; 600 mg/kg); and KATP channel pathways were tested using the ATP-sensitive K+ channel blocker, glibenclamide-hippuric acid (GHA, 2 mg/kg). Potential effects of BEO on motor coordination were assessed using a rotarod test. RESULTS: BEO exerted analgesic effects in all pain models. Notably, pretreatment with naltrindole, naloxone, or L-arginine significantly reduced the analgesic effects of BEO in the formalin test. BEO increased mean withdrawal latencies in a thermal plantar test at a high dose, but not at lower doses. BEO had no effect on motor coordination. CONCLUSIONS: Our findings indicate that the analgesic effects of BEO are primarily mediated by delta- and mu-opioid pathways and further suggest that BEO has potential for development as an analgesic agent for the relief of inflammatory pain.

The High Performance of Crystal Water Containing Manganese Birnessite Cathodes for Magnesium Batteries.

Rechargeable magnesium batteries have lately received great attention for large-scale energy storage systems due to their high volumetric capacities, low materials cost, and safe characteristic. However, the bivalency of Mg(2+) ions has made it challenging to find cathode materials operating at high voltages with decent (de)intercalation kinetics. In an effort to overcome this challenge, we adopt an unconventional approach of engaging crystal water in the layered structure of Birnessite MnO2 because the crystal water can effectively screen electrostatic interactions between Mg(2+) ions and the host anions. The crucial role of the crystal water was revealed by directly visualizing its presence and dynamic rearrangement using scanning transmission electron microscopy (STEM). Moreover, the importance of lowering desolvation energy penalty at the cathode-electrolyte interface was elucidated by working with water containing nonaqueous electrolytes. In aqueous electrolytes, the decreased interfacial energy penalty by hydration of Mg(2+) allows Birnessite MnO2 to achieve a large reversible capacity (231.1 mAh g(-1)) at high operating voltage (2.8 V vs Mg/Mg(2+)) with excellent cycle life (62.5% retention after 10000 cycles), unveiling the importance of effective charge shielding in the host and facile Mg(2+) ions transfer through the cathode's interface.