Pathogenic bacterial infections have become a major health problem worldwide. New antimicrobial agents are urgently needed to overcome this problem. In this study, antibacterial activity of Nigella sativa seed extract against some pathogenic bacterial strains (Streptococcus pyogene, Pseudomonas aeruginosa, Klebseilla pneumoniae and Proteus vulgaris) was evaluated. Methanol extract at the concentration of 100 mg/mL had a remarkable sensitivity towards all tested bacteria in this study. Klebseila pneumonia and Proteus vulgaris showed resistance against aqueous extract at 20 mg/mL. Methanol extract of Nigella sativa exhibited significant antibacterial activity at the concentration of 50 mg/mL (p ≤ 0.01) against Streptococcus pyogenes with a greater inhibition zone of 19 mm, while a 15 mm zone of inhibition was observed in Pseudomonas aeruginosa, Klebseilla pneumonia and Proteus vulgaris. Kruskal Wallis analysis showed that both aqueous and methanol extract of black seed exhibited a greater inhibition on Gram positive bacteria (Streptococcus pyogenes) compared with Gram negative bacteria (Pseudomonas aeruginosa, Klebseilla pneumoniae and Proteus vulgaris). Our study also showed that species, strains and concentrations of Nigella sativa extract are some of the factors that may influence the sensitivity of the tested bacteria. A significant correlation was observed between zone of inhibition and concentration of extract.
Endophytic fungi are those living inside the host plant without causing any apparent negative effect on the host plant. Two
isolates endophytic fungi from leaves and two isolates from root at Universiti Teknologi MARA (UiTM) Reserve Forest,
Negeri Sembilan were successfully isolated and identified by morphology and molecular characteristic. Samples were
surface sterilized and sub-cultured to obtain a pure culture. Characteristics of the isolates such as colony appearance,
mycelial texture, conidia/spores and pigmentation were studied to explore their morphology. Isolates were also subjected to
a PCR-based genotyping test. There were noticeable differences in morphological characteristics among the four isolates.
Microscopic analysis showed four isolates consist of septa and conidia/spores. The pigmentation result showed that
colony in A1leaf samples demonstrated an orange color on potato dextrose agar (PDA) media, colony in A1root demonstrate
a black texture in PDA media while hairy colonies in the others two isolates showed a white color on PDA media. Based on
molecular analyses the fungal genera showed 99-100% similarity with the related fungi recorded in the GenBank. Both
morphology and molecular sequencing of internal transcribed spacer (ITS) regions of endophytic fungi showed that three
isolates (A1root, C2leaf, and C3root) were grouped in Basidiomycota while one isolate (A1leaf) belonged to Ascomycota. The
endophyte funguses were identified as Daldinia sp. (A1leaf), Polyporales sp. (A1root,) Lentinus sp. (C2leaf,) and Rigidoporus
sp. (C3root). Overall, the new discoveries of isolated endophyte fungal have dyeing potential of fungal pigments which
offer a viable alternative to natural vegetable and harmful synthetic dyes.