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Decoctions and macerations of the stem bark and wood of Terminalia brownii Fresen. are used in traditional medicine for fungal infections and as fungicides on field crops and in traditional granaries in Sudan. In addition, T. brownii water extracts are commonly used as sprays for protecting wooden houses and furniture. Therefore, using agar disc diffusion and macrodilution methods, eight extracts of various polarities from the stem wood and bark were screened for their growth-inhibitory effects against filamentous fungi commonly causing fruit, vegetable, grain and wood decay, as well as infections in the immunocompromised host. Ethyl acetate extracts of the stem wood and bark gave the best antifungal activities, with MIC values of 250 µg/mL against Nattrassia mangiferae and Fusarium verticillioides, and 500 µg/mL against Aspergillus niger and Aspergillus flavus. Aqueous extracts gave almost as potent effects as the ethyl acetate extracts against the Aspergillus and Fusarium strains, and were slightly more active than the ethyl acetate extracts against Nattrassia mangiferae. Thin layer chromatography, RP-HPLC-DAD and tandem mass spectrometry (LC-MS/MS), were employed to identify the chemical constituents in the ethyl acetate fractions of the stem bark and wood. The stem bark and wood were found to have a similar qualitative composition of polyphenols and triterpenoids, but differed quantitatively from each other. The stilbene derivatives, cis- (3) and trans- resveratrol-3-O-β-galloylglucoside (4), were identified for the first time in T. brownii. Moreover, methyl-(S)-flavogallonate (5), quercetin-7-β-O-di-glucoside (8), quercetin-7-O-galloyl-glucoside (10), naringenin-4′-methoxy-7-pyranoside (7), 5,6-dihydroxy-3′,4′,7-tri-methoxy flavone (12), gallagic acid dilactone (terminalin) (6), a corilagin derivative (9) and two oleanane type triterpenoids (1) and (2) were characterized. The flavonoids, a corilagin derivative and terminalin, have not been identified before in T. brownii. We reported earlier on the occurrence of methyl-S-flavogallonate and its isomer in the roots of T. brownii, but this is the first report on their occurrence in the stem wood as well. Our results justify the traditional uses of macerations and decoctions of T. brownii stem wood and bark for crop and wood protection and demonstrate that standardized extracts could have uses for the eco-friendly control of plant pathogenic fungi in African agroforestry systems. Likewise, our results justify the traditional uses of these preparations for the treatment of skin infections caused by filamentous fungi.

Combretum padoides Engl. & Diels, C. psidioides Welv. and C. zeyheri Sond. are used forthe treatment of infections and tuberculosis related symptoms in African traditional medicine. In orderto verify these uses, extracts were screened for their growth inhibitory eects against M. smegmatisATCC 14468. Ultra-high pressure liquid chromatography coupled to quadrupole time-of-flightmass spectrometry (UHPLC/QTOF-MS) and GC-MS were used to investigate the polyphenoliccomposition in the active extracts. The lowest minimum inhibitory concentration (MIC), 625 g/mL,was shown by a methanol extract of the stem bark of C. psidioides. A butanol extract of C. psidioidesgave large inhibition zone diameters (IZD 21 mm) and inhibited 84% of the mycobacterial growthat 312 g/mL. Combretastatin B-2 and dihydrostilbene derivatives were present in the methanolextract of C. psidioides, whereas the butanol extract of this species contained punicalagin, corilagin,and sanguiin H-4. Methanol and butanol extracts of the stem bark of C. padoides gave large inhibitionzone diameters (IZD 26.5 mm) and MIC values of 1250 and 2500 g/mL, respectively. C. padoidescontained an ellagitannin with a mass identical to punicalagin ([M-H]− 1083.0587) and a corilaginlike derivative ([M-H]− 633.0750) as well as ellagic acid arabinoside and methyl ellagic acid xyloside.A butanol extract of the roots of C. zeyheri showed mild antimycobacterial activity and containeda gallotannin at m/z [M-H]− 647.0894 as the main compound along with punicalagin and threeunknown ellagitannins at m/z [M-H]− 763.0788, 765.0566, and 817.4212. Our results indicate thatthe studied species of Combretum contain phenolic and polyphenolic compounds with possiblepotential as leads for antimycobacterial drugs or as adjuvants for conventional anti-TB drugs.

Our results show that T. laxiflora and T. brownii contain antimycobacterial compounds of diverse polarities and support the traditional uses of various parts of T. laxiflora and T.brownii as decoctions for treatment of tuberculosis. Further investigations are warranted to explore additional (new) antimycobacterial compounds in the active extracts of T. laxiflora and T. brownii.

In Sudanese traditional medicine, decoctions of the stem bark of Anogeissus leiocarpa are used for the treatment of tuberculosis (TB). However, this plant has not been investigated before for its antimycobacterial effects. Our screening results show, for the first time, that many extracts of various parts of A. leiocarpa exhibit growth inhibitory activity against Mycobacterium smegmatis. Minimum inhibitory concentration (MIC) values ranged between 625 and 5000 µg/mL, with an ethyl acetate extract of the root showing the lowest MIC value. The good antimycobacterial effects of the root part could be due to its high concentration of ellagic acid derivatives, ellagitannins, and flavonoids. Thin layer chromatography (TLC) fractionation resulted in some fractions with better activity than the starting point crude methanol extract (MIC 2500 µg/mL). Those fractions with the lowest MIC values contained a high number of antioxidant compounds. Fractions 3 and 4 (MIC 1500 and 1000 µg/mL, respectively) contained high concentrations of di-methyl ellagic acid ([M-H]− 329.0318). Fraction 6 (MIC 2000 µg/mL) contained a lower concentration of di-methyl ellagic acid and was not as growth inhibitory as fractions 3 and 4. Moreover, in fraction 3, an acetylated ellagic acid derivative ([M-H]− 343.0477) and di-methyl-ellagic acid xyloside ([M-H]− 461.0739) were tentatively characterized. Di-methyl ellagic acid xyloside was also present in fraction 4 and could strongly contribute to the antimycobacterial effect of this fraction. Additionally, protocatechuic acid ([M-H]− at m/z 153.0196) was present in fraction 4. Our antimycobacterial results obtained from this research justify the use of A. leiocarpa in Sudanese folk medicine against cough related to TB. Roots, stem bark, and leaves of A. leiocarpa are sources for new potent anti-TB drug lead compounds.

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Bacterial and fungal resistance to antibiotics is of growing global concern. Plants such as the African Combretum and Pteleopsis species, which are used in traditional medicine for the treatment of infections, could be good sources for antimicrobial extracts, drug scaffolds, and/or antibiotic adjuvants. In African countries, plant species are often used in combinations as traditional remedies. It is suggested that the plant species enhance the effects of each other in these combination treatments. Thus, the multi-species-containing herbal medications could have a good antimicrobial potency. In addition, plant extracts and compounds are known to potentiate the effects of antibiotics. The objective of this review is to compile the information on the botany, ethnopharmacology, ethnobotany, and appearance in herbal markets of African species of the genera Combretum and Pteleopsis. With this ethnobotanical information as a background, this review summarizes the information on the phytochemistry and antimicrobial potency of the extracts and their active compounds, as well as their combination effects with conventional antibiotics. The databases used for the literature search were Scopus, Elsevier, EBSCOhost, PubMed, Google Scholar, and SciFinder. In summary, a number of Combretum and Pteleopsis species were reported to display significant in vitro antibacterial and antifungal efficacy. Tannins, terpenes, flavonoids, stilbenes, and alkaloids—some of them with good antimicrobial potential—are known from species of the genera Combretum and Pteleopsis. Among the most potent antimicrobial compounds are arjunglucoside I (MIC 1.9 µg/mL) and imberbic acid (MIC 1.56 µg/mL), found in both genera and in some Combretum species, respectively. The in vitro antimicrobial properties of the extracts and compounds of many Combretum and Pteleopsis species support their traditional medicinal uses.