The genus Commicarpus (Nyctaginaceae) includes about 30-35 species distributed over the tropical and subtropical regions of the world, especially in Africa and western Asia.1 C. grandiflorus (A. Rich.) Standl. is one of the five species growing wild in Saudi Arabia where its leaves aqueous extract is popularly used to kill lice by washing the hair2 and to treat lower limb weakness and rheumatism.3 The aerial parts of C. grandiflorus produce large amounts of slimy, sticky exudates, which sometimes cause death to insects that land on the surface of the plant. A previous phytochemical study of the plant aerial parts revealed the presence of flavonol 3-O-glucosides, betulinic acid, and β-sitosterol4, while some biological studies were mainly aimed to the investigation of antimicrobial activity of the crude extracts: the methanol extract demonstrated antimicrobial activity against Pseudomonas aeruginosa, Proteus vulgaris, Staphylococcus aureus, Sarcina lutea, Mycobacterium phlei, Bacillus subtilis, Candida albicans, and Escherichia coli5; the ether petroleum subfraction of the methanolic extract showed a potent antiprotozoal effect against Plasmodium falciparum, Trypanosoma brucei, T. cruzi, and Leishmania infantum.6 The aim of this work was the chemical investigation of the C. grandiflorus flowering aerial part exudate collected in the mountains of the Taif region in Saudi Arabia. Four methylated flavones and five triterpenes were isolated and characterized by 1D and 2D NMR and mass spectrometry, including two new triterpenes, 2α,3β,11α-olean-18-en-2,3,11-triol (1) and 2α,3β-olean-12-en-2,3-diol-11-one (2) (named commicarpotriol and commicarpodiol, respectively). Moreover, the overall antimicrobial activity of all isolated compounds was evaluated against a collection of Gram-positive and Gram-negative bacteria. Results showed that compound 1, eucalyptin, and 8-demethylsideroxylin were active against Streptococcus mutans, while only eucalyptin was active against Staphylococcus aureus. All other isolated compounds were not active.
Two new triterpenes from Commicarpus grandiflorus (A. Rich.) Standl. aerial parts exudate
M. Di Stasi;M. De Leo;A. Braca
2022-01-01
Abstract
The genus Commicarpus (Nyctaginaceae) includes about 30-35 species distributed over the tropical and subtropical regions of the world, especially in Africa and western Asia.1 C. grandiflorus (A. Rich.) Standl. is one of the five species growing wild in Saudi Arabia where its leaves aqueous extract is popularly used to kill lice by washing the hair2 and to treat lower limb weakness and rheumatism.3 The aerial parts of C. grandiflorus produce large amounts of slimy, sticky exudates, which sometimes cause death to insects that land on the surface of the plant. A previous phytochemical study of the plant aerial parts revealed the presence of flavonol 3-O-glucosides, betulinic acid, and β-sitosterol4, while some biological studies were mainly aimed to the investigation of antimicrobial activity of the crude extracts: the methanol extract demonstrated antimicrobial activity against Pseudomonas aeruginosa, Proteus vulgaris, Staphylococcus aureus, Sarcina lutea, Mycobacterium phlei, Bacillus subtilis, Candida albicans, and Escherichia coli5; the ether petroleum subfraction of the methanolic extract showed a potent antiprotozoal effect against Plasmodium falciparum, Trypanosoma brucei, T. cruzi, and Leishmania infantum.6 The aim of this work was the chemical investigation of the C. grandiflorus flowering aerial part exudate collected in the mountains of the Taif region in Saudi Arabia. Four methylated flavones and five triterpenes were isolated and characterized by 1D and 2D NMR and mass spectrometry, including two new triterpenes, 2α,3β,11α-olean-18-en-2,3,11-triol (1) and 2α,3β-olean-12-en-2,3-diol-11-one (2) (named commicarpotriol and commicarpodiol, respectively). Moreover, the overall antimicrobial activity of all isolated compounds was evaluated against a collection of Gram-positive and Gram-negative bacteria. Results showed that compound 1, eucalyptin, and 8-demethylsideroxylin were active against Streptococcus mutans, while only eucalyptin was active against Staphylococcus aureus. All other isolated compounds were not active.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
