HPLC-DAD and UHPLC/QTOF-MS Analysis of Polyphenols in Extracts of the African Species Combretum padoides, C. zeyheri and C. psidioides Related to Their Antimycobacterial Activity

Abstract

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.

Ethnopharmacology, Antimicrobial Potency, and Phytochemistry of African Combretum and Pteleopsis Species (Combretaceae): A Review

“…Most studies on the antibacterial effects of Combretum species on bacteria that cause respiratory diseases have used only one bacterium, either Pseudomonas aeruginosa or Klebsiella pneumoniae, although a multitude of bacterial strains, such as Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenza, Corynebacterium diphteriae, Bordetella pertussis, and Mycobacterium tuberculosis are known to cause respiratory diseases [22]. Moreover, to date, C. psidioides, C. padoides, C. zeyheri, C. hartmannianum, C. molle, C. apiculatum, C. imberbe, and C. hereroense are the species that have so far been screened for their antimycobacterial effects, although there are still many Combretum species used for tuberculosis (TB) that have not been scientifically validated [23,51,107,[110][111][112][113]. For example, C. micranthum is used for TB in Guinean traditional medicine, but there is no literature available about its antimycobacterial potential.…”

“…Moreover, there are several herbal formulations of plant extracts from the Pteleopsis and Combretum species, in both African and international markets, that are briefly discussed in this review [20]. In accordance with their traditional uses for the treatment of infection, numerous in vitro studies have confirmed that African Combretum species possess antibacterial and antifungal properties [22,23]. Species of the genus Pteleopsis have been studied to a lesser extent, although there are reports confirming the antimicrobial activities of P. myrtifolia and P. suberosa [24,25].…”

“…Most of the studies report on the activities of extracts and, in some cases, active compounds have been isolated. Antimicrobial compounds in Combretum and Pteleopsis species include ellagitannins, ellagic acid derivatives, gallotannins, terpenoids, In accordance with their traditional uses for the treatment of infection, numerous in vitro studies have confirmed that African Combretum species possess antibacterial and antifungal properties [22,23]. Species of the genus Pteleopsis have been studied to a lesser extent, although there are reports confirming the antimicrobial activities of P. myrtifolia and P. suberosa [24,25].…”

Traditional Uses and Anticancer Potential of the Combretum Genus: A Literature Review

“…They are first isolated from the South African Combretum caffrum specie [59]. Other Combretum species also contain these molecules [60,61]. Combretastatins are simple compounds formed of two phenyl rings linked by a chain of two carbon atoms.…”

Natural Products and Their Derivatives with Antibacterial, Antioxidant and Anticancer Activities

“…This study further extends the range of compounds that are produced by the genus Simplicillium. Fyhrquist et al [ 6 ], who also followed the bioactivity-guided fractionation approach, used water and solvents (methanol, butanol and chloroform) to extract several phenolic and polyphenolic compounds from three species of the Combretum genus in a search for anti-mycobacterial activity. Active extracts were analyzed by ultrahigh-pressure liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UHPLC/QTOF–MS) and GC–MS.…”