This study compared different commercially available viability reagents. The growth indicator reagents includep-iodonitrotetrazolium violet (INT), PrestoBlue, and Alamar Blue which were used for antimicrobial analysis againstStreptococcus mutans,Prevotella intermedia,Propionibacterium acnes, andMycobacterium tuberculosis. PrestoBlue and Alamar Blue are resazurin based reagents that resulted in a quick and easily distinguishable colour change that allowed for visual readings. INT and Sodium 3′-[1-(phenyl amino-carbonyl)-3,4-tetrazolium]-bis-[4-methoxy-6-nitro] benzene sulfonic acid hydrate (XTT) are tetrazolium based reagents which are converted to a formazan dye in the presence of metabolically active mitochondria enzyme. For cell viability analysis, reagents XTT and PrestoBlue were compared. PrestoBlue was able to clearly indicate the minimum inhibitory concentration (MIC) of various positive drug controls on various microbial strains. PrestoBlue was also a good indicator of the 50% inhibitory concentration (IC₅₀) of positive drug controls on various cell lines.

Root extracts of Pelargonium reniforme CURT and Pelargonium sidoides DC were evaluated for antibacterial and antifungal assays using the agar dilution while antitubercular assays were done using the BACTEC method at concentrations ranging from 5×103 to 500.0 mg/L. The ethanol and acetone extracts of the roots of P. sidoides inhibited the growth of Haemophilus influenzae, Moraxella catarrhalis and Streptococcus pneumoniae at a concentration of 5×103 mg/L. Both acetone and ethanol extracts of P. reniforme and only the ethanol extract of P. sidoides inhibited the growth of Aspergillus niger and Fusarium oxysporum significantly at a concentration of 5×103 mg/L. Growth of Rhizopus stolonifer was suppressed by the ethanol extract of P. reniforme and P. sidoides at 5×103 and 1×103 mg/L, respectively. Acetone, chloroform and ethanol extracts of P. reniforme showed activity against M. tuberculosis exhibiting a minimum inhibitory concentration of 5×103 mg/L