title: Protease-inhibiting, molecular modeling and antimicrobial activities of extracts and constituents from Helichrysum foetidum and Helichrysum mechowianum (compositae).
abstract: BACKGROUND
  Helichrysum species are used extensively for stress-related ailments and as dressings for wounds normally encountered in circumcision rites, bruises, cuts and sores. It has been reported that Helichysum species are used to relief abdominal pain, heart burn, cough, cold, wounds, female sterility, menstrual pain.
  
  
  RESULTS
  From the extracts of Helichrysum foetidum (L.) Moench, six known compounds were isolated and identified. They were 7, 4'-dihydroxy-5-methoxy-flavanone (1), 6'-methoxy-2',4, 4'-trihydroxychalcone (2), 6'-methoxy-2',4-dihydroxychalcone -4'-O-β-D-glucoside (3), apigenin (4), apigenin-7-O-β-D-glucoside (5), kaur-16-en-18-oic acid (6) while two known compounds 3,5,7-trihydroxy-8-methoxyflavone (12), 4,5-dicaffeoyl quinic acid (13) together with a mixture of phytosterol were isolated from the methanol extract of Helichrysum mechowianum Klatt. All the compounds were characterized by spectroscopic and mass spectrometric methods, and by comparison with literature data. Both extracts and all the isolates were screened for the protease inhibition, antibacterial and antifungal activities. In addition, the phytochemical profiles of both species were investigated by ESI-MS experiments.
  
  
  CONCLUSIONS
  These results showed that the protease inhibition assay of H. foetidum could be mainly attributed to the constituents of flavonoids glycosides (3, 5) while the compound (13) from H. mechowianum contributes to the stomach protecting effects. In addition, among the antibacterial and antifungal activities of all the isolates, compound (6) was found to possess a potent inhibitor effect against the tested microorganisms. The heterogeneity of the genus is also reflected in its phytochemical diversity. The differential bioactivities and determined constituents support the traditional use of the species. Molecular modelling was carried out by computing selected descriptors related to drug absorption, distribution, metabolism, excretion and toxicity (ADMET). Graphical abstractCompounds isolated from Helichrysum species (Compositae).
authors.affiliation: Department of Pharmacy, University of Douala, Douala, P.O. Box 812, Cameroon.
authors.forename: Fanny-Aimée Essombe
authors.initials: FA
authors.lastname: Malolo
authors.affiliation: Department of Chemistry, University of Douala, Douala, P.O. Box 567 24157, Cameroon.
authors.forename: Achille
authors.initials: A
authors.lastname: Bissoue Nouga
authors.affiliation: Department of Chemistry, University of Douala, Douala, P.O. Box 567 24157, Cameroon.
authors.forename: Antoine
authors.initials: A
authors.lastname: Kakam
authors.affiliation: Department of Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, Weinberg 3, D-06120 Halle (Saale), Germany.
authors.forename: Katrin
authors.initials: K
authors.lastname: Franke
authors.affiliation: Department of Pharmacy, University of Douala, Douala, P.O. Box 812, Cameroon.
authors.forename: Lidwine
authors.initials: L
authors.lastname: Ngah
authors.affiliation: Química, Departamento de Química Orgânica, Núcleo de Bioensaio, Biossíntese e Ecofisiologia de Produtos Naturais-NuBBE, Universidade Estadual Paulista (UNESP) Instituto de Rua Prof. Francisco Degni s/n, Araraquara, São Paulo 14.800-900 Brazil.
authors.forename: Otavio
authors.initials: O
authors.lastname: Flausino
authors.affiliation: Department of Pharmacy, University of Douala, Douala, P.O. Box 812, Cameroon.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Mpondo Mpondo
authors.affiliation: Chemical and Bioactivity Information Centre, Department of Chemistry, University of Buea, P. O. Box 63, Buea, Cameroon.
authors.forename: Fidele
authors.initials: F
authors.lastname: Ntie-Kang
authors.affiliation: Department of Pharmacy, University of Douala, Douala, P.O. Box 812, Cameroon.
authors.forename: Jean Claude
authors.initials: JC
authors.lastname: Ndom
authors.affiliation: Química, Departamento de Química Orgânica, Núcleo de Bioensaio, Biossíntese e Ecofisiologia de Produtos Naturais-NuBBE, Universidade Estadual Paulista (UNESP) Instituto de Rua Prof. Francisco Degni s/n, Araraquara, São Paulo 14.800-900 Brazil.
authors.forename: Vanderlan da Silva
authors.initials: Vda S
authors.lastname: Bolzani
authors.affiliation: Department of Bioorganic Chemistry, Leibniz Institute of Plant Biochemistry, Weinberg 3, D-06120 Halle (Saale), Germany.
authors.forename: Ludger
authors.initials: L
authors.lastname: Wessjohann
keywords: Antimicrobial; Compositae; ESI-MS; Helichrysum foetidum; Helichysum mechowianum; Protease inhibition assay