Litsea glutinosa (Lauraceae): Evaluation of its Foliar Phytochemical Constituents for Antimicrobial Activity

Abstract

The phytochemical investigation of the leaves of Litsea glutinosa revealed the presence of secondary metabolites like alkaloids, anthraquinones, cardiac glycosides, flavonoids, glycosides, phenols, saponins, steroids, tannins, terpenoids, volatile compounds, amino acids and carbohiydrates. The antimicrobial activity and minimum inhibition concentration values were determined for these phytochemical constituents as crude extracts using the agar well diffusion and two-fold serial dilution methods. The results indicated that Bacillus subtilis was the most susceptible bacterium with high inhibition zones for the methanol and chloroform extracts of 31 mm and 26 mm, respectively. The MIC values indicated that extracts possess good antimicrobial activity with significant MIC value against Enterococcus faecalis, Pseudomonas aeruginosa and Staphylococcus pneumoniae at 31.2 µg/ml concentrations. The extracts showed marked antimicrobial activity against both bacteria and fungi. Among the bacterial strains, gram-positive bacteria were more susceptible than the gram-negative. All the 13 microorganisms tested showed dose dependent susceptibility towards the phytochemicals present in the foliar extracts. The study suggests that Litsea glutinosa leaves possess potent antimicrobial activity and can be a good source for the development of new antibiotics.

Ethnomedicinal Uses, Phytochemistry, and Therapeutic Potentials of Litsea glutinosa (Lour.) C. B. Robinson: A Literature-Based Review

“…In another study, the results indicated that extracts (hexane, chloroform, and methanol) of L. glutinosa possess good antimicrobial activity with significant minimum-inhibitory-concentration (MIC) values against E. faecalis , P. aeruginosa , and Staphylococcus pneumoniae at 31.2 μg/mL [ 8 ]. In addition, methanolic leaf-extract and ethanolic bark-extract [ 46 ] of L. glutinosa showed effective antimicrobial effects in a dose-dependent manner against the test microbes.…”

“…Robinson, belongs to the family Lauraceae, and is a medicinal plant of immense pharmaceutical value that reaches a height of approximately 3–15 m and whose bark is 2–2.5 cm thick, with a brown surface [ 7 ]. It is a polymorphic species with leaves that are simple, elliptical-to-oblong-elliptical, pilose when young, 3.5–10 × 1.5–11 cm, and with unisexual flowers that are yellow in color and 5–6 mm across, along with fruits, a berry that is 5–6 mm across and which may be purple, on a flat disc [ 8 , 9 ]. L. glutinosa is native to India, South China, Malaysia, Australia, the western Pacific Islands, Bhutan, Myanmar, Nepal, Philippines, Thailand and Vietnam, in the forest of Chittagong and the Sylhet districts in Bangladesh [ 7 , 10 ].…”

“…L. glutinosa is native to India, South China, Malaysia, Australia, the western Pacific Islands, Bhutan, Myanmar, Nepal, Philippines, Thailand and Vietnam, in the forest of Chittagong and the Sylhet districts in Bangladesh [ 7 , 10 ]. L. glutinosa is known as Maida Lakri, sycamore, Indian laurel [English]; bolly beech, brown bollygum, brown bollywood, brown beech, soft bollygum [English/Australia]; Indiese lourier [Afrikaans]; avocat marron, litsée glutineuse [French]; bois d’oiseau [French/Mauritius]; puso-puso, sablot [Tagalog]; bời lời đỏ [Vietnamese]; কুকুরচিতা [Bengali]; 潺槁木姜子 [Chinese]; หมูทะลวง [Thai] [ 7 , 8 , 11 , 12 ].…”

“…Traditionally, the bark acts as one of the most prevalent folk medicines, exerting medicinal values for treating diarrhea, dysentery, abdominal pain, indigestion, gastroenteritis, edema, traumatic injuries, colds, arthritis, asthma, diabetes and as a treatment for pain relief and for poignant sexual power [ 8 , 13 ], while the leaves exert antibacterial and cardiovascular activities, as well as the extreme flow of semen in male [ 7 ]. The leaves can also be used as a topical medicine to heal wounds and bruises, as well as providing an emollient action to relieve the stresses of rheumatic and gouty joints [ 11 ].…”

“…Litsea glutinosa is a small to a medium-sized plant which can be 3–20 m tall with straight or curved stems up to 60 cm in diameter. According to Mohammad et al (2020) this plant species contains a mean tree-height of 13.24 (m), mean clear-bole height of 4.61 (m), mean girth at breast height of 62.89 (cm), mean crown-radius of 2.51 (m), mean crown-diameter of 5.17 (m), mean crown-height of 8.63 (m), mean number of primary branches, 5.46, mean leaf area, 91.09 (cm 2 ), mean leaf-weight, 0.55 (gm), mean specific leaf-area, 175.7 (cm 2 /g), and mean bark wt./unit area, 2.75 (g) [ 8 ]. This species contains gray-yellow silky young branchlets, on which leaves are oval-shaped but adjustable and of 7–15 × 3–7 cm, alternately arranged and 1–2.6 cm long [ 10 ].…”