Diverse limonoids from barks of Toona ciliata var. yunnanensis and their biological activities

Four New Limonoids from the Barks of Toona ciliata

“…The clearly diagnostic signals (Table 1) for a β-substituted furan moiety, five characteristic singlet methyl groups in the 1D NMR spectra, and the correlations of a methoxy group (δ H 3.72) with an ester carbonyl carbon (δ C 170.8) in the HMBC spectrum suggested that toonayunnanae I (4) was likely a B-seco limonoid with a C6-C7-methyl ester appendage [5,8,[14][15][16], similar to toonayunnanin G (6) [15]. Comparison of the 1D NMR Fig.…”

“…The 1 H and 13 C NMR data of 1 (Table 1 ) showed characteristic resonances for a β -substituted furan ring ( δ H 7.35, 7.16, 6.20; δ C 111.2, 124.7, 139.4, 142.8), an α,β -unsaturated ketone ( δ H 7.08 d, J = 10.4 Hz, 5.98 d, J = 10.4 Hz; δ C 125.7, 155.0, 204.3), and five singlet methyl groups ( δ H 0.54, 1.05, 1.11, 1.29, 1.54). Those observations together with 26 carbon resonances and 11 indices of hydrogen deficiency, suggested that 1 might be a ring-intact limonoid with an α,β- unsaturated carbonyl moiety in A ring [ 8 – 10 ] (Fig. 1 ).…”

“…2 ) from H-7 ( δ H 4.82) to C-8 ( δ C 47.1) and C-6 ( δ C 26.3); from H 3 -30 ( δ H 1.54) to C-7 ( δ C 81.5) and C-14 ( δ C 96.8); from H 3 -18 ( δ H 0.54) and H-15 ( δ H 4.62) to C-14; and from H 2 -16 and H-17 to C-15 ( δ C 77.7) indicated that C-7, C-14, and C-15 were all oxygenated. The significantly deshielded chemical shift of C-14 and the indices of hydrogen deficiency suggested the presence of an oxetane ring between C-7 and C-14 [ 8 , 11 , 12 ] and a hydroxy group at C-15, similar to that in ciliatasecone S [ 8 ]. Therefore, the 2D structure of 1 with a rare oxetane ring was constructed.…”

“…493.2561) and its 13 C NMR data. Apart from the signals for an acetoxy substituent, the remaining 26 carbon resonances observed in the 1D NMR spectra indicated that 2 might also be a ring-intact limonoid [ 8 – 10 ]. Comparison of its NMR data (Table 1 ) with those of the known toonaciliatone F ( 5 ) [ 13 ] revealed that the main differences were the absence of a double bond and an acetoxy group.…”

“…henryi and T. ciliata var. yunnanensis have led to the isolation of a series of limonoids with potential biological activities such as cytotoxicity, anti-inflammatory, and anti-multidrug resistance (MDR) activities [4][5][6][7][8]. As a part of our continuous research for bioactive limonoids from Toona plants, four new limonoids, toonayunnanaes F − I (1 − 4), and six known compounds (5 − 10) were isolated from the barks of T. ciliata.…”