Bioactive flavonoids from plant extract of Pyrethrum pulchrum and its acute toxicity

Abstract

Pyrethrum pulchrum Ledeb. has been a phytochemically unexplored Mongolian medicinal folklore plant. In this study, its total flavonoid content was determined and fourteen flavonoids (1-14) were isolated from the aerial parts of P. pulchrum. Their structures were elucidated on the basis of spectroscopic data. The compounds 12-14, methoxyflavones, were tested for antiproliferative and cytotoxic activity against A549, HeLa, K-562, THP-1 and HUVEC cell lines. This is the first report on the effects of 5,7,4'-trihydroxy-3,6,3'-trimethoxyflavone ( 13) against all tested cell lines and it exhibited potent activity against chronic myeloid leukemia K-562 and acute monocytic leukemia THP-1 cells, each with GI 50 value at 2.0 μg/mL. The 5,4 'dihydroxy-3,6,7,3'-tetramethoxyflavone (14) showed the most potent activity against THP-1 (GI 50 = 1.1 μg/mL) and the highest cytotoxicity (5.6 μg/mL). In addition, acute toxicity of plant ethanol extract was evaluated and the lethal dose (LD 50 ) was estimated at 1058 mg/kg.

New Guaianolide Sesquiterpene Lactones and Other Constituents from Pyrethrum pulchrum

“…5.58 (1H, br s, H-3) and a pair of geminally coupled protons at δ H 6.12 (1H, dd, J = 1.5, 3.2 Hz, Ha-13) and 6.26 (1H, dd, J = 1.5, 3.2 Hz, Hb-13), 2 signals for oxygenated methines at δ H 4.01 (1H, dd, J = 9.9, 10.2 Hz, H-6) and 3.82 (1H, dd, J = 4.5, 9.9 Hz, H-8), 2 signals for methine protons at δ H 3.06 (1H, br d, J = 10.2 Hz, H-5) and 2.57 (1H, ddd, J = 3.2, 9.9, 10.2 Hz, H-7) together with 2 methylene signals at δ H 2.81 and 2.09 (each, br d, J = 17.5 Hz, Ha-2, Hb-2) and 2.28 (2H, dd, J = 4.5, 9.3 Hz, H-9), as well as 2 methyl signals at δ H 1.95 (3H, br s, H-15) and 1.34 (3H, s, H-14). 13 C and HSQC NMR data revealed 15 carbon signals including 1 carbonyl at δ C 172.4 (C-12) and 2 olefinic carbons at δ C 123.3 (C-13) and 126.2 (C-3). In addition, signals for 4 aliphatic methines at δ C 52.3 (C-5), 56.9 (C-7), 67.9 (C-8), and 81.5 (C-6), 2 methylenes at δ C 38.9 (C-2) and 45.0 (C-9), 2 methyls at δ C 18.6 (C-15) and 22.8 (C-14), and 4 non-protonated carbons at δ C 62.2 (C-10), 73.8 (C-1), 139.3 (C-11), and 141.5 (C-4) with sp 3 and sp 2 hybridizations were present.…”

“…HPLC-HR-ESI-MS analysis showed quasi- [18]. The remaining spin system forms an aliphatic chain, bearing olefinic protons on one ▶ Table 1 1 H and 13 C NMR (500 MHz and 125 MHz) data of compounds 1 and 2 (δ in ppm, J in Hz). 4, the presence of a triple bond was confirmed at C-8 and C-9.…”

“…1 ). Fourteen flavonoids ( 14 – 27 ) have been described in our previous work 13 . The chemical structures of compounds 1 – 13 are shown in Fig.…”

“…Arglabin (3), the major sesquiterpene lactone found in the methanol extract of P. pulchrum, exhibited the highest activity against human cancer lines, while compound 1 also possesses significant antiproliferative activity against leukemia cells. biological activities [13], no chemical studies have been conducted on this species, to the best of our knowledge.…”

“…Except for our previous chemical investigations of P. pulchrum that focused on the identification of constituents of the essential oil 12 and the characterization of 14 flavonoids along with their biological activities 13 , no chemical studies have been conducted on this species, to the best of our knowledge.…”