0000000001304791
AUTHOR
Stephen S. Nyandoro
showing 19 related works from this author
Modified ent-Abietane Diterpenoids from the Leaves of Suregada zanzibariensis
2022
The leaf extract of Suregada zanzibariensis gave two new modified ent-abietane diterpenoids, zanzibariolides A (1) and B (2), and two known triterpenoids, simiarenol (3) and β-amyrin (4). The structures of the isolated compounds were elucidated based on NMR and MS data analysis. Single-crystal X-ray diffraction was used to establish the absolute configurations of compounds 1 and 2. The crude leaf extract inhibited the infectivity of herpes simplex virus 2 (HSV-2, IC50 11.5 μg/mL) and showed toxicity on African green monkey kidney (GMK AH1) cells at CC50 52 μg/mL. The isolated compounds 1–3 showed no anti-HSV-2 activity and exhibited insignificant toxicity against GMK AH1 cells at ≥100 μM. p…
Polyoxygenated Cyclohexenes and Other Constituents of Cleistochlamys kirkii Leaves.
2016
Thirteen new metabolites, including the polyoxygenated cyclohexene derivatives cleistodiendiol (1), cleistodienol B (3), cleistenechlorohydrins A (4) and B (5), cleistenediols A-F (6-11), cleistenonal (12), and the butenolide cleistanolate (13), 2,5-dihydroxybenzyl benzoate (cleistophenolide, 14), and eight known compounds (2, 15-21) were isolated from a MeOH extract of the leaves of Cleistochlamys kirkii. The purified metabolites were identified by NMR spectroscopic and mass spectrometric analyses, whereas the absolute configurations of compounds 1, 17, and 19 were established by single-crystal X-ray diffraction. The configuration of the exocyclic double bond of compound 2 was revised base…
N-Cinnamoyltetraketide Derivatives from the Leaves of Toussaintia orientalis
2015
Seven N-cinnamoyltetraketides (1−7), including the new Ztoussaintine E (2), toussaintine F (6), and toussaintine G (7), were isolated from the methanol extract of the leaves of Toussaintia orientalis using column chromatography and HPLC. The configurations of E-toussaintine E (1) and toussaintines A (3) and D (5) are revised based on single-crystal X-ray diffraction data from racemic crystals. Both the crude methanol extract and the isolated constituents exhibit antimycobacterial activities (MIC 83.3−107.7 μM) against the H37Rv strain of Mycobacterium tuberculosis. Compounds 1, 3, 4, and 5 are cytotoxic (ED50 15.3−105.7 μM) against the MDA-MB-231 triple negative aggressive breast cancer cel…
Crotofolane Diterpenoids and Other Constituents Isolated from Croton kilwae
2023
Six new crotofolane diterpenoids (1-6) and 13 known compounds (7-19) were isolated from the MeOH- CH2Cl2 (1:1, v/v) extracts of the leaves and stem bark of Croton kilwae. The structures of the new compounds were elucidated by extensive analysis of spectroscopic and mass spectrometric data. The structure of crotokilwaepoxide A (1) was confirmed by single -crystal X-ray diffraction, allowing for the determination of its absolute configuration. The crude extracts and the isolated compounds were investigated for antiviral activity against respiratory syncytial virus (RSV) and human rhinovirus type-2 (HRV-2) in HEp-2 and HeLa cells, respectively, for antibacterial activity against the Gram-posit…
A New Benzopyranyl Cadenane Sesquiterpene and Other Antiplasmodial and Cytotoxic Metabolites from Cleistochlamys kirkii
2019
Phytochemical investigations of ethanol root bark and stem bark extracts of Cleistochlamys kirkii (Benth.) Oliv. (Annonaceae) yielded a new benzopyranyl cadinane-type sesquiterpene (cleistonol, 1) alongside 12 known compounds (2&ndash
Secoiridoids and Iridoids from Morinda asteroscepa
2020
The new 2,3-secoiridoids morisecoiridoic acids A (1) and B (2), the new iridoid 8-acetoxyepishanzilactone (3), and four additional known iridoids (4–7) were isolated from the leaf and stem bark methanol extracts of Morinda asteroscepa using chromatographic methods. The structure of shanzilactone (4) was revised. The purified metabolites were identified using NMR spectroscopic and mass spectrometric techniques, with the absolute configuration of 1 having been established by single-crystal X-ray diffraction analysis. The crude leaf extract (10 μg/mL) and compounds 1–3 and 5 (10 μM) showed mild antiplasmodial activities against the chloroquine-sensitive malaria parasite Plasmodium falciparum (…
Flavonoids from Erythrina schliebenii
2017
Prenylated and O-methylflavonoids including one new pterocarpan (1), three new isoflavones (2–4), and nineteen known natural products (5–23) were isolated and identified from the root, stem bark, and leaf extracts of Erythrina schliebenii. The crude extracts and their constituents were evaluated for antitubercular activity against Mycobacterium tuberculosis (H37Rv strain), showing MICs of 32–64 μg mL–1 and 36.9–101.8 μM, respectively. Evaluation of their toxicity against the aggressive human breast cancer cell line MDA-MB-231 indicated EC50 values of 13.0–290.6 μM (pure compounds) and 38.3 to >100 μg mL–1 (crude extracts).
CCDC 1497772: Experimental Crystal Structure Determination
2017
Related Article: Stephen S. Nyandoro, Joan J. E. Munissi, Amra Gruhonjic, Sandra Duffy, Fangfang Pan, Rakesh Puttreddy, John P. Holleran, Paul A. Fitzpatrick, Jerry Pelletier, Vicky M. Avery, Kari Rissanen, Máté Erdélyi|2017|J.Nat.Prod.|80|114|doi:10.1021/acs.jnatprod.6b00759
CCDC 1963302: Experimental Crystal Structure Determination
2020
Related Article: Linda Zandi, Marco Makungu, Joan J. E. Munissi, Sandra Duffy, Rakesh Puttreddy, Daniel von der Heiden, Kari Rissanen, Vicky M. Avery, Stephen S. Nyandoro, Máté Erdélyi|2020|J.Nat.Prod.|83|2641|doi:10.1021/acs.jnatprod.0c00447
CCDC 1937081: Experimental Crystal Structure Determination
2019
Related Article: Stephen S. Nyandoro, Gasper Maeda, Joan J.E. Munissi, Amra Gruhonjic, Paul A. Fitzpatrick, Sofia Lindblad, Sandra Duffy, Jerry Pelletier, Fangfang Pan, Rakesh Puttreddy, Vicky M. Avery, Máté Erdélyi|2019|Molecules|24|2746|doi:10.3390/molecules24152746
CCDC 1498874: Experimental Crystal Structure Determination
2017
Related Article: Stephen S. Nyandoro, Joan J. E. Munissi, Msim Kombo, Clarence A. Mgina, Fangfang Pan, Amra Gruhonjic, Paul Fitzpatrick, Yu Lu, Bin Wang, Kari Rissanen, Máté Erdélyi|2017|J.Nat.Prod.|80|377|doi:10.1021/acs.jnatprod.6b00839
CCDC 1497770: Experimental Crystal Structure Determination
2017
Related Article: Stephen S. Nyandoro, Joan J. E. Munissi, Amra Gruhonjic, Sandra Duffy, Fangfang Pan, Rakesh Puttreddy, John P. Holleran, Paul A. Fitzpatrick, Jerry Pelletier, Vicky M. Avery, Kari Rissanen, Máté Erdélyi|2017|J.Nat.Prod.|80|114|doi:10.1021/acs.jnatprod.6b00759
CCDC 1498877: Experimental Crystal Structure Determination
2017
Related Article: Stephen S. Nyandoro, Joan J. E. Munissi, Msim Kombo, Clarence A. Mgina, Fangfang Pan, Amra Gruhonjic, Paul Fitzpatrick, Yu Lu, Bin Wang, Kari Rissanen, Máté Erdélyi|2017|J.Nat.Prod.|80|377|doi:10.1021/acs.jnatprod.6b00839
CCDC 1498873: Experimental Crystal Structure Determination
2017
Related Article: Stephen S. Nyandoro, Joan J. E. Munissi, Msim Kombo, Clarence A. Mgina, Fangfang Pan, Amra Gruhonjic, Paul Fitzpatrick, Yu Lu, Bin Wang, Kari Rissanen, Máté Erdélyi|2017|J.Nat.Prod.|80|377|doi:10.1021/acs.jnatprod.6b00839
CCDC 1498875: Experimental Crystal Structure Determination
2017
Related Article: Stephen S. Nyandoro, Joan J. E. Munissi, Msim Kombo, Clarence A. Mgina, Fangfang Pan, Amra Gruhonjic, Paul Fitzpatrick, Yu Lu, Bin Wang, Kari Rissanen, Máté Erdélyi|2017|J.Nat.Prod.|80|377|doi:10.1021/acs.jnatprod.6b00839
CCDC 1498876: Experimental Crystal Structure Determination
2017
Related Article: Stephen S. Nyandoro, Joan J. E. Munissi, Msim Kombo, Clarence A. Mgina, Fangfang Pan, Amra Gruhonjic, Paul Fitzpatrick, Yu Lu, Bin Wang, Kari Rissanen, Máté Erdélyi|2017|J.Nat.Prod.|80|377|doi:10.1021/acs.jnatprod.6b00839
CCDC 1498878: Experimental Crystal Structure Determination
2017
Related Article: Stephen S. Nyandoro, Joan J. E. Munissi, Msim Kombo, Clarence A. Mgina, Fangfang Pan, Amra Gruhonjic, Paul Fitzpatrick, Yu Lu, Bin Wang, Kari Rissanen, Máté Erdélyi|2017|J.Nat.Prod.|80|377|doi:10.1021/acs.jnatprod.6b00839
CCDC 1497771: Experimental Crystal Structure Determination
2017
Related Article: Stephen S. Nyandoro, Joan J. E. Munissi, Amra Gruhonjic, Sandra Duffy, Fangfang Pan, Rakesh Puttreddy, John P. Holleran, Paul A. Fitzpatrick, Jerry Pelletier, Vicky M. Avery, Kari Rissanen, Máté Erdélyi|2017|J.Nat.Prod.|80|114|doi:10.1021/acs.jnatprod.6b00759
CCDC 1937082: Experimental Crystal Structure Determination
2019
Related Article: Stephen S. Nyandoro, Gasper Maeda, Joan J.E. Munissi, Amra Gruhonjic, Paul A. Fitzpatrick, Sofia Lindblad, Sandra Duffy, Jerry Pelletier, Fangfang Pan, Rakesh Puttreddy, Vicky M. Avery, Máté Erdélyi|2019|Molecules|24|2746|doi:10.3390/molecules24152746