Antimicrobial,anti-inflammatory and antioxidant activities of natural organic matter extracted from cretaceous shales in district Nowshera-Pakistan

Traditionally, Natural Organic Matter (NOM) derived from cretaceous rocks has been used for treatment of various ailments such as diabetes, inflammation and skin infections. This study evaluated the antimicrobial, antioxidant and anti-inflammatory activities of natural organic matter obtained from cretaceous shales. The shales were collected from Lumshiwal formation; located north of the main Kala Chitta range in district Nowshera-Pakistan. Isolation was done by sonicating crushed rock sample with chloroform, methanol and acetone (70: 15: 15 v/v, respectively). Antibacterial and antifungal activity of sample was determined by agar well diffusion and Agar slanting methods, respectively. In vitro anti-inflammatory activity was performed using cyclooxygenase-2 and 5-lipoxygenase enzymes. Antioxidant activity was assessed for scavenging of DPPH, superoxide anions, hydroxyl radicals, and hydrogen peroxide. In vivo anti-inflammatory activity was performed using “Carrageenan-induced paw edema model”. The sample showed significant antibacterial activity against Salmonella typhi, Pseudomonas aeruginosa and Escherichia coli with MIC values 0.82, 0.87 and 0.79 mg/ml, respectively. Considerable inhibition was observed against Bacillus subtilis (MIC; 0.93 mg/ml) and Staphylococcus aureus (MIC; 1.12 mg/ml) when compared with Imipenem as a standard. Moreover, the sample displayed significant antifungal activity against Alternaria alternata and Fusarium solani with MIC values of 0.60 and 0.68 mg/ml, respectively. Both COX-2 (IC₅₀ 31.34 µg/ml) and 5-LOX (IC₅₀ 38.45 µg/ml) enzymes were inhibited by NOM in a concentration-dependent manner. In addition, the NOM exhibited significant free radical scavenging, especially against DPPH and superoxide anions; and a moderate effect on hydroxyl and hydrogen peroxide scavenging. In vivo anti-inflammatory activity revealed that the edema volume was significantly (P < 0.001) decreased at all doses when compared with control and maximum activity (33, 47 and 54% at 50, 100 and 200 mg/kg dose, respectively) was observed at fifth hr of treatment. Likewise, the inhibition capacity was increased with dose. The present findings showed that cretaceous shales may contain a variety of medicinal agents that are traditionally believed to possess properties useful in the treatment of various ailments particularly skin and inflammatory disorders. Therefore, these shales could be a new source for activity-guided isolation of antimicrobial, antioxidant, and anti-inflammatory agents.