Evaluation of Antioxidant, Antibiofilm, Cytotoxic and AntimicrobialActivities of Calligonum Comosum

Abstract

Objective: Calligonum Comosum is a native omani medicinal plants used traditionally by the locals to treat inflammation, toothache, gum sores and ulcer. As antimicrobial resistance poses a serious threat on global scale by rendering many currently available antibiotics ineffective. This demands the need to look for novel therapeutic agents and there has been an expanded interest in natural products as sources of pharmacologically active principles. The present study was thus initiated to corroborate the therapeutic uses of this medicinal species by evaluating, the phyto-constituents, antibacterial, anti-biofilm and antioxidant activities of C. comosum. Methods: Quantitative and qualitative phytochemical analysis was done, using standard protocols. The antioxidant activity was assessed applying DPPH free radical scavenging assay, hydrogen peroxide radical scavenging assay and the total antioxidant capacity. Biofilm inhibition activity was evaluated using micro titer plate assay and well diffusion method was employed to determine the antibacterial activity. Cytotoxity was assessed in terms of LC50 value using brine shrimp lethality assay. Results: The methanolic extracts of C. comosum showed significant antibacterial activity against all the five tested bacterial strains, with MIC values for all observed to be 1.25 mg/ml except for E. coli. Substantial reduction of the biofilm formation was observed for all bacterial species treated with C. comosum leaf and stem extracts and the extracts also displayed significant cytotoxicity against brine shrimp nauplii, exhibiting LC50 value of 56.797 μg/ml. The total phenolic content and flavonoid content was observed to be 56.6 ± 1.66 mg GAE/g and 49.33 ± 1.34 mg of QE/g of dry extract respectively. C. comosum exhibited potent DPPH scavenging activity, with IC50 value of 44.90 μg/ml and the total antioxidant capacity was 130 ± 2.04 mg AAE/g. Conclusion: The result validates its ethno-medicinal use and suggests that the C. comosum can be exploited for its antibiofilm, antioxidant and antibacterial properties.