title: Cytotoxic triterpenoid saponins acylated with monoterpenic acids from fruits of Gleditsia caspica Desf.
abstract: Four bisdesmosidic triterpenoid saponins named caspicaosides A-D, were isolated from the fruits of Gleditsia caspica Desf. Their structures were determined by NMR spectroscopy including HOHAHA, ¹H-¹H COSY, ROE, HMQC, HMBC experiments and HRFAB-MS as well as acid hydrolysis. The four 3,28-O-bisdesmosidic triterpenoid saponins comprised echinocystic acid as the aglycone and common oligosaccharide moieties at C3 and C28. The saccharide moiety at C-3 was identified as β-D-xylopyranosyl-(1→2)-α-L-arabinopyranosyl-(1→6)-β-D-glucopyranosyl while that at C-28 was determined as β-D-xylopyranosyl-(1→3)-β-d-xylopyranosyl-(1→4)-α-L-rhamnopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→6)-]β-D-glucopyranosyl. The pentasaccharide moiety linked to C-28 was acylated with monoterpenic acid and or monoterpene-arabinoside moieties at C-2 or C-2 and C-3 of the terminal rhamnose unit. The isolated saponins were assayed for their in vitro cytotoxicities against the three human tumor cell lines HepG2, A549 and HT29 using MTT method. The results showed that caspicaosides B and C bearing two and three monoterpene units, respectively, exhibited significant cytotoxic activities against the used cell lines with IC₅₀ values 1.5-6.5 μM. Caspicaosides A and D with one monoterpene unit exhibited significant cytotoxic activities on HepG2 cell line with IC₅₀ values equal to 4.5 and 5.4 μM, respectively, and IC₅₀ values > 10 μM against the other two cell lines. The number of monoterpene units seems to play a main role in determining the activity.
authors.affiliation: School of Pharmaceutical Sciences, University of Shizuoka, Shizuoka 422-8526, Japan.
authors.forename: Toshio
authors.initials: T
authors.lastname: Miyase
authors.forename: F R
authors.initials: FR
authors.lastname: Melek
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Warashina
authors.forename: M A
authors.initials: MA
authors.lastname: Selim
authors.forename: N M
authors.initials: NM
authors.lastname: El Fiki
authors.forename: I A A
authors.initials: IA
authors.lastname: Kassem
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D004354:Drug Screening Assays, Antitumor; D004534:Egypt; D005638:Fruit / Q000737:chemistry; D031501:Gleditsia / Q000737:chemistry*; D006801:Humans; D020128:Inhibitory Concentration 50; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D012503:Saponins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D014315:Triterpenes / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D012503:Saponins; D014315:Triterpenes; C554987:caspicaoside B; C554988:caspicaoside C