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.

Terminalia laxiflora Engl. & Diels, (Sudanese Arabic name: Darout الدروت) and Terminalia brownii Fresen (Sudanese Arabic name: Alshaf ألشاف) (Combretaceae) are used in Sudanese traditional folk medicine and in other African countries for treatment of infectious diseases, TB and its symptoms, such as cough, bronchitis and chest pain. Because of the frequent use of T. laxiflora and T. brownii in African traditional medicine and due to the absence of studies regarding their antimycobacterial potential there was a need to screen extracts of T. laxiflora and T. brownii for their growth inhibitory potential and to study the chemical composition and compounds in growth inhibitory extracts. The plant species were collected in Sudan (Blue Nile Forest, Ed Damazin Forestry areas) and selected according to their uses in traditional medicine for the treatment of bacterial infections, including TB. Eighty extracts and fractions of the stem bark, stem wood, roots, leaves and fruits of T. laxiflora and T. brownii and nine pure compounds present in the active extracts were screened against Mycobacterium smegmatis ATCC 14468 using agar diffusion and microplate dilution methods. Inhibition zones and MIC values were estimated and compared to rifampicin. HPLC-UV/DAD, GC/MS and UHPLC/Q-TOF MS were employed to identify the compounds in the growth inhibitory extracts. The roots of T. laxiflora and T. brownii gave the best antimycobacterial effects (IZ 22-27 mm) against Mycobacterium smegmatis. The lowest MIC of 625 µg/ml was observed for an acetone extract of the root of T. laxiflora followed by methanol and ethyl acetate extracts, both giving MIC values of 1250 µg/ml. Sephadex LH-20 column chromatography purification of T. brownii roots resulted in low MIC values of 62.5 µg/ml and 125 µg/ml for acetone and ethanol fractions, respectively, compared to 5000 µg/ml for the crude methanol extract. Methyl (S)-flavogallonate is suggested to be the main active compound in the Sephadex LH- 20 acetone fraction, while ellagic acid xyloside and methyl ellagic acid xyloside are suggested to give good antimycobacterial activity in the Sephadex LH-20 ethanol fraction. RP-18 TLC purifications of an ethyl acetate extract of T. laxiflora roots resulted in the enrichment of punicalagin in one of the fractions (Fr5). This fraction gave a five times smaller MIC (500 µg/ml) than the crude ethyl acetate extract (2500 µg/ml) and this improved activity is suggested to be mostly due to punicalagin. 1,18-octadec-9-ene-dioate, stigmast-4-en-3-one, 5α-stigmastan-3,6-dione, triacontanol, sitostenone and β-sitosterol were found in antimycobacterial hexane extracts of the stem bark of both studied species. Of these compounds, 1,18-octadec-9-ene-dioate, stigmast-4-en-3-one, 5α-stigmastan-3,6-dione, triacontanol, sitostenone have not been previously identified in T. brownii and T. laxiflora. Moreover, both plant species contained friedelin, betulinic acid, β-amyrine and two unknown oleanane-type triterpenoids. Of the listed compounds, friedelin, triacontanol and sitostenone gave a MIC of 250 µg/ml against M. smegmatis, whereas stigmasterol and β-sitosterol gave MIC values of 500 µg/ml. 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.

Ten crude extracts and their solvent partition fractions from five species of Terminalia collected in Tanzania were assessed for antimycobacterial effects using Mycobacterium smegmatis ATCC 14468 as a model organism. We report here, for the first time, on antimycobacterial effects of root and stem bark extracts of Terminalia sambesiaca and Terminalia kaiserana as well as of fruit extracts of Terminalia stenostachya and leaf extracts of Terminalia spinosa. T. sambesiaca gave the best effects of all the investigated species in terms of the sizes of the inhibitory zones of root and stem bark extracts. A crude methanol root extract of T. sambesiaca gave lower MIC values (1250μg/ml) than its aqueous and butanol soluble fractions (MIC 2500μg/ml). Our preliminary HPLC–DAD data indicates that methanol and aqueous extracts of T. sambesiaca roots are rich in ellagitannins and ellagic acid glycosides. Particularly, one polar ellagitannin at tR 10.3–10.9min dominates the extracts quantitatively and thus may be responsible for their good antimycobacterial effects. In contrast to the more polar fractions, a chloroform soluble fraction of the roots of T. sambesiaca was devoid of antimycobacterial activity. Also crude methanol and aqueous extracts of the stem bark of T. sambesiaca gave promising antimycobacterial effects (MIC 1250μg/ml). All fractions of T. kaiserana roots, except from the aqueous insoluble gave good antimycobacterial effects (MIC 1250μg/ml) and the aqueous extract showed the best effects of the fractions in terms of the size of inhibition zones. These results justify the uses of hot water decoctions of the roots of T. kaiserana for treatment of cough, one of the symptoms of TB. According to HPLC–DAD data methanol extracts of T. kaiserana roots and their aqueous fractions are rich in polar ellagitannins and ellagic acid glycosides. Quantitatively, the ellagitannins dominate these extracts and therefore the good antimycobacterial activity of the methanol and aqueous extracts is assumed to be due to these compounds. Sephadex LH-20 CC fractions of a methanol extract of the roots of T. kaiserana inhibited the growth of M. smegmatis, giving MIC values of 1000μg/ml. Ellagic acid glycosides in these fractions must be responsible for their good antimycobacterial effects since they are present in high concentrations. Good antimycobacterial effects were also obtained with a root extract of Terminalia sericea, and especially the butanol soluble fraction was a good inhibitor of the growth of M. smegmatis (MIC 1562μg/ml). Our preliminary HPLC–DAD results show that the roots of T. sericea are rich in ellagitannins, ellagic acid glycosides and at least one stilbene compound. Extracts of the fruits of T. stenostachya gave good antimycobacterial effects, butanol extracts being the most active. Also the leaves of T. stenostachya, and especially the butanol soluble extracts, give good antimycobacterial effects. Our HPLC–DAD data indicate that T. stenostachya leaves contain large quantities of gallic acid, ellagitannins and ellagic acid glycosides. Our results indicate that many of the investigated species of Terminalia might contain leads for development of anti-TB drugs. Standardized extracts of T. sambesiaca, T. kaiserana and T. sericea roots could be used as easily available and cheap medicines for treatment of TB in remote regions of East and South Africa

This study reports for the first time promising antibacterial and antifungal effects of epidihydropinidine, the major piperidine alkaloid in the needles and bark of Norway spruce, Picea abies (L.) Karsten. Epidihydropinidine was growth inhibitory against all bacterial and fungal strains used in our investigation, showing the lowest MIC value of 5.37μg/mL against Pseudomonas aeruginosa, Enterococcus faecalis, Candida glabrata and C. albicans. Epidihydropinidine was nearly three times more active than tetracycline against P. aeruginosa and E. faecalis. Promising antibacterial effects were also recorded against Staphylococcus aureus and Bacillus cereus (MIC 10.75μg/mL) as well as against Salmonella enterica (MIC and MBC 43μg/mL). Our preliminary results suggest that epidihydropinidine as well related alkaloids of Norway spruce could be powerful candidates for new antibiotics and for preventing food spoilage.

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.