Phytochemical characterization and biological activities of Plectranthus barbatus Andrews

Abstract

Plectranthus barbatus Andrews (Lamiaceae) is widely distributed in the world and has a range of popular therapeutic indications. This work aimed to evaluate the phytochemical characterization of two leaf extracts of P. barbatus, and their antimicrobial, antineoplastic and immunomodulatory potential. After collection, herborization and obtainment of the P. barbatus aqueous extract (PBA) and acetone:water 7:3 P. barbatus organic extract (PBO), the phytochemical characterization was performed by high-performance liquid chromatography (HPLC). The antimicrobial activity was performed to determine the minimum inhibitory concentration (MIC) against eight bacterial strains using the microdilution test and the fungus Trichophyton rubrum by disc diffusion assay and microdilution test. Cytotoxicity was assessed by MTT and trypan blue methods in normal peripheral blood mononuclear cells (PBMCs) at concentrations ranged between 0.1 to 100 µg.mL-1 and in neoplastic cell lines Toledo, K562, DU-145 and PANC-1 at 1, 10 and 100 µg.mL-1 . Immunomodulatory activity, was evaluated by sandwich ELISA of proinflammatory cytokines at BALB/c mice splenocytes cultures supernatant. Both extracts presented flavonoids, cinnamic derivatives, steroids and ellagic acid. PBO showed bacteriostatic activity against Acinetobacter baumannii (MIC = 250 µg.mL-1) clinical isolate and PBA fungistatic activity against Trichophyton rubrum (MIC = 800 µg.mL-1). The extracts did not exhibit toxicity to PBMCs and neoplastic cells (IC50 > 100 µg.mL-1). Additionally, PBO at 100 µg.mL-1 significantly inhibited IFN-γ and IL-17A cytokines (p = 0.03). Plectranthus barbatus is a potential candidate for therapeutic use due to its low toxicity in healthy human cells and exhibits biological activities of medical interest as bacteriostatic, fungistatic and immunomodulatory.

HPLC/DAD, Antibacterial and Antioxidant Activities of Plectranthus Species (Lamiaceae) Combined with the Chemometric Calculations

“…Mothana et al [30], evaluating the antibacterial potential of Plectranthus species, demonstrated the inhibitory potential of P. barbatus and its hexanic, chloroformic, and butanolic fractions against Gram-positive strains with MIC ranging from 62.5 to 312.5 µg/mL, corroborating the results obtained. The aqueous and aqueous aceto extracts of P. barbatus leaves showed MIC against E. coli, P. aeruginosa and two strains of MRSA ≥ 500 µg/mL, showing lower effectiveness than the extract under study [9].…”

“…In addition, the genus is recognized for its biological activities, such as antimicrobial, anticancer, antiparasitic, repellent, immunomodulating activity, among others. Its bioactivities are related to its content of phenolic compounds, proving to be rich in flavonoids, especially flavones, flavonols and flavonones, and phenolic acids, such as trans-rosmarinic acid [4,[9][10][11][12].…”

Phytochemistry and biological activities of the floral hydroethanolic extract of Ipomoea carnea Jacq. (Convolvulaceae)

“…The floral extract was the filtered and concentrated to dryness by using rotary evaporator. The obtained extract was dried (freeze drying) and stored at -12 °C until further analysis described by Cordeiro et al (2022) modified.…”

Phytochemical profile and biological activities of Bromelia antiacantha extracts

“…Natural products, especially those of plant origin, represent the main sources of active substances with potential therapeutic use and the oldest source of medicines ever used by humans (Moga et al, 2016;Cordeiro et al, 2021). Knowledge of the nutritional and medicinal properties of a country's biodiversity species, especially plants, has been the basis for the development of society and human survival, as they bring benefits to science and to the national bioeconomy (Rodrigues and De Simoni, 2010).…”