Two triterpenoids from Rubus fraxinifolius leaves and their tyrosinase and elastase inhibitory activities

Numerous therapeutic compounds have been isolated from naturally abundant organic resources, which may offer economical and sustainable sources of compounds with safe and efficacious biological activities. In the cosmetics industry, natural compounds with anti-aging activities are eagerly sought. Thus, we prepared various extracts from Rubus fraxinifolius leaves and used enzyme inhibition assays to isolate compounds with protective effects against skin aging. Two triterpenoids were isolated from Rubus fraxinifolius Poir. leaves. The structures were characterized by spectroscopic analyses (LC-ESI-MS, 1D/2D NMR) and comparison to reported data. Compound 1 and 2 were determined as 2,3-O-ethyleneglycol, 19-hydroxyurs-12-en-23,28-dioic acid and 2,3-O-propanediol,19-hydroxyurs-12-en-28-oic acid. Methanol extract and isolates were assessed for their inhibitory effects on elastase and tyrosinase. Compounds 1 and 2 inhibited elastase with IC50 122.199 µg/mL and 98.22 µg/mL, and also inhibited tyrosinase with IC50 207.79 µg/mL and 221.51 µg/mL, respectively. The molecular docking proved that both compounds have affinities toward the enzymes.

A new phenanthrene derivative from Entada abyssinica with antimicrobial and antioxidant properties

Entada abyssinica Steud. Ex A. Rich (Leguminosae) is a medicinal plant used traditionally for the treatment of infections. A phytochemical investigation of the methanol extract of E. abyssinica root bark led to the isolation of a new phenanthrene derivative named phenentada (1), together with seven known compounds (8 S, 13 E)-kolavic acid 15-methyl ester (2) and 8 S-kolavic acid 15-methyl ester (3) obtained as mixture, 8 S-kolavic acid 15-methyl ester (3), 8 S-kolavic acid 18-methyl ester (4), 13,14,15,16-tetranorclerod-3-ene-12,18-dioic acid (5), 1′,26′-bis-[(S)-2,3-dihydroxypropyl] hexacosanedioate (6), campesterol (7) and 3-O-β -d-glucopyranosylstigmasterol (8). Their structures were determined by NMR spectroscopy (1D and 2D), mass spectrometry (HRESIMS) and by comparison with previously reported data. The crude extract and some isolated compounds were evaluated for their in vitro antimicrobial activities by the microdilution method while, the antioxidant activity was evaluated by the DPPH methods. Regarding the antimicrobial activity, the crude extract showed significant inhibitory activities against bacteria strains (MIC 7.81–31.3 μg mL−1) and yeasts (MIC 15.6–31.3 μg mL−1) whereas all compounds tested exhibited significant activity against Staphylococcus epidermidis. Moreover, compounds 4, 5 and 6 and the mixture 2/3 showed significant antimicrobial activity on Candida parapsilosis strain (MIC = 3.12 μg mL−1), as well as selected antifungal property against candida pathogenic fungi strains. On the other hand, compounds (1) demonstrated the best bioactivities against Candida albicans and Salmonella enterica with MIC = 3.12 μg mL−1 while the mixture 2/3 appeared to have the highest inhibition on gram (+) bacteria strain S. epidermidis with MIC of 0.78 μg mL−1 and compound 5 (MIC = 1.56 μg mL−1) against the gram (−) bacteria strain. Furthermore, the SC50 values measured by the antioxidant test for all samples varied between 47.21 and 52.44 μg mL−1 for DPPH. These results support the traditional uses of E. abyssinica in the management of several diseases including the claim in the skin disease treatment. Additionally, here is reported the first time isolation of a phenanthrene derivative in the Fabaceae family to the best of our knowledge.

Identification of the CoA-ester intermediates and genes involved in the cleavage and degradation of the steroidal C-ring by Comamonas testosteroni TA441

Comamonas testosteroni TA441 degrades steroids aerobically via aromatization of the A-ring accompanied by B-ring cleavage, followed by D- and C-ring cleavage. We previously revealed major enzymes and intermediate compounds in A,B-ring cleavage, β-oxidation cycle of the cleaved B-ring, and partial C,D-ring cleavage process. Here, we elucidated the C-ring cleavage and the β-oxidation cycle that follows. ScdL1L2, a 3-ketoacid Coenzyme A (CoA) transferase which belongs to the SugarP_isomerase superfamily, was thought to cleave the C-ring of 9-oxo-1,2,3,4,5,6,10,19-octanor-13,17-secoandrost-8(14)-ene-7,17-dioic acid-CoA ester, the key intermediate compound in the degradation of 9,17-dioxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid (3aα- H -4α [3′-propionic acid]-7aβ-methylhexahydro-1,5-indanedione; HIP)-CoA ester in the previous study; however, this study suggested that ScdL1L2 is the isomerase of the derivative with a hydroxyl group at C-14 which cleaves C ring. The subsequent ring-cleaved product was indicated to be converted to 4-methyl-5-oxo-octane-1,8-dioic acid-CoA ester mainly by ORF33-encoded CoA-transferase (named ScdJ), followed by dehydrogenation by ORF21 and 22-encoded acyl-CoA dehydrogenase (named ScdM1M2). Then a water molecule is added by ScdN for further degradation by β-oxidation. ScdN is considered to catalyze the last reaction in C,D-ring degradation by the enzymes encoded in the steroid degradation gene cluster tesB to tesR . IMPORTANCE Studies on bacterial steroid degradation were initiated more than 50 years ago primarily to obtain materials for steroid drugs. Steroid-degrading bacteria are globally distributed, and the role of bacterial steroid degradation in the environment as well as in human is attracting attention. The overall degradation of steroidal four rings is proposed, however there are still much to be revealed to understand the complete degradation pathway. This study aims to uncover the whole steroid degradation process in C. testosteroni , which is one of the most studied representative steroid degrading bacteria and is suitable for exploring the degradation pathway because the involvement of degradation-related genes can be determined by gene disruption.

Isolation and Identification of two Triterpenoids from Ethyl acetate extract of Bark of Boehmeria rugulosa

Column chromatography of purified ethyl acetate extract of bark part of Boehmeria rugulosa afforded triterpenoids (3-oxo-20-demethylisoaleuritolic-28,29-dioic acid and 3-oxo-20-demethylisoaleuritolic-28,30-dioic acid.). Structure of these compounds was elucidated using spectroscopic techniques. This is the first report of isolation of this compound from bark of B. rugulosa.

Identification of the CoA-ester intermediates and genes involved in the cleavage and degradation of the steroidal C-ring by Comamonas testosteroni TA441

Comamonas testosteroni TA441 degrades steroids aerobically via aromatization of the A-ring accompanied by B-ring cleavage, followed by D- and C-ring cleavage. We previously revealed major enzymes and intermediate compounds in A,B-ring cleavage, β-oxidation cycle of the cleaved B-ring, and partial C,D-ring cleavage process. Here, we elucidated the C-ring cleavage and the β-oxidation cycle that follows. ScdL1L2, a 3-ketoacid Coenzyme A (CoA) transferase which belongs to the SugarP_isomerase superfamily, was thought to cleave the C-ring of 9-oxo-1,2,3,4,5,6,10,19-octanor-13,17-secoandrost-8(14)-ene-7,17-dioic acid-CoA ester, the key intermediate compound in the degradation of 9,17-dioxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid (3aα-H-4α [3′-propionic acid]-7aβ-methylhexahydro-1,5-indanedione; HIP)-CoA ester in the previous study; however, this study suggested that ScdL1L2 is the isomerase of the derivative with a hydroxyl group at C-14 which cleaves C ring. The subsequent ring-cleaved product was indicated to be converted to 4-methyl-5-oxo-octane-1,8-dioic acid-CoA ester mainly by ORF33-encoded CoA-transferase (named ScdJ), followed by dehydrogenation by ORF21 and 22-encoded acyl-CoA dehydrogenase (named ScdM1M2). Then a water molecule is added by ScdN for further degradation by β-oxidation. ScdN is considered to catalyze the last reaction in C,D-ring degradation by the enzymes encoded in the steroid degradation gene cluster tesB to tesR.