Antibacterial and Antibiotic-Modifying Activity of Methanol Extracts from Six Cameroonian Food Plants against Multidrug-Resistant Enteric Bacteria
Table 1
Plants used in the present study and evidence of their bioactivities.
Species (family); voucher
Traditional uses
Parts used traditionally
Bioactive or potentially bioactive components
Bioactivity of crude extract
Psidium guajava Linn. (Myrtaceae); 2884/SRF/Cam
To treat wounds, lesions, ulcers, diarrhea, cholera, hypertension, and obesity and the control of diabetes mellitus [8]. Anti-inflammatory effect, cough, diabetes, kidney problems, diarrhea, tonic, laxative, antihelminthic [9], conjunctivitis, oral care, and antispasmodic [10].
Leaves, fruits, flowers, bark, and roots
Tannins, flavonoids (myricetin, quercetin, luteolin and kaempferol), essential oils (caryophyllene, nerolidol, β-bisabolene, aromadendrene, p-selinene, α-pinene and 1,8-cineol), triterpenoids (oleanic acid, ursolic acid, catecholic acid, guayavolic acid, maslinic acid, ellagic acid) and β-sitosterol [11]; essential oil: propylbenzene, allyl benzene, and so forth [12].
Antibacterial activity of essential oil: Sa, Sf, Lspp, Esa, Aspp, Ec, Pv, Ea, St, Pa, andKp [12]; antioxidant activity of leaves essential oil [13]. Ethanolic extract of leaves: Ec, Kp, Pa, Sa, Ab, MRSA, and VRE [14]; antiproliferative, antiseptic and antifungal activity [9]; ethanolic extract of leaves: antioxidant, antitumor, and antibacterial (against Sm, Smt, and Sor) [15].
Persea americana Mill. (Lauraceae); 57756/HNC
Anticancer activity, the food industry has grown tremendous interest in processing this crop and enhancing its value [16]. P. americana leaves’ extracts have been used as analgesic, anti-inflammatory, hypoglycaemic, anticonvulsant, antidiabetic, and vasorelaxant [17].
Methanol, chloroform, ethyl acetate, and petroleum ether leaves extracts were tested against Ec, St, Sa, Ca, Pa,and Bs; antioxidant activity [18]; aqueous leaves’ extract: anti-inflammatory and analgesic activity [17].
Citrus sinensis Linn. (Rutaceae); 25859/HNC
Treat ailments like constipation, cramps, colic, diarrhea, bronchitis, tuberculosis, cough, cold, obesity, menstrual disorder, angina, hypertension, anxiety, depression, and stress [19]; used to soothe sore throats, indigestion, relieve intestinal gas and bloating and resolve phlegm and as an additive for flavoring to our foods [20].
Leaves, flowers, seeds, peel, fruits, and barks
Polyphenols (caffeic acid, p-coumaric acid, ferulic acid, and sinapinic acid), flavonoids (hesperidin, narirutin, naringin, eriocitrin) [21], essential oil composition: D-limonene, β-myrcene, α-pinene, β-pinene, γ-terpinene, α-terpinolene, α-caryophyllene, copaene, β-phellandrene [22] and many other constituents.
Ethanolic extracts of peels and juice (Q): Sta, Sau, Sm, Ss,Kp, and Ec [20]; ethanolic extracts of peels: Sta, Pv, Kp, Ec, Bs, and Pa [23]; crude extract of juice (Q): Ec, Sta, and MRSA [24]; crude extracts from different parts of the plants reduce high blood pressure, respiratory problems, rheumatism [25, 26], and anticancer, antimicrobial, and antioxidant activity [22].
The stomachic bark decoction is used to treat dysentery in Liberia and the bark powder decoction is used in equatorial Africa to stimulate appetite and counteract anemia [27].
Leaves, stem bark, fruits, and roots
Ethanolic extract of leaves, stem bark and roots: alkaloids, flavonoids, tannins, saponins, terpenes, and cardiac glycosides [27].
Ethanolic extracts of bark and leaves: Pa, Sa, Ec, St, and Ca [27]. Methanolic extract of the bark: antiplasmodial activity [28].
Carotenoids (provitamin A compound, beta-carotene, lutein, and alpha-carotene), polyphenols [30] such as quercetin, kaempferol, gallic acid, caffeic acid, catechins, tannins, and mangiferin [31].
Mangiferin: anticancer (breast, renal, colon and leukemia cancer cell lines [32, 33]; antidiabetic [34]; antimalarial [35]; methanol and aqueous extracts: Sa, Sp, Pa, Ca, and Ef [36]; Se, Lm, Ec [37]; ethanol and benzene extracts: Pv, Pf, Sfx, Kp, and St [38]; antiamoebic [39].
Polyphenols (catechins and their derivatives), methylxanthines (caffeine, theophylline and theobromine), carbohydrates, proteins, free amino acids, vitamins (vitamin C and carotenoids), volatile compounds, lipids, chlorophylls, saponins and inorganic elements (fluorine, manganese and aluminum) [40, 41].
Methanolic extract of leaves: antioxidant activity. These antioxidant properties are beneficial for several chronic diseases related to oxidative stress, including cancer and cardiovascular and neurodegenerative diseases [42].
