LAUSR

Mentha haplocalyx Briq. belongs to the genus Mentha (family Labiatae). Its aerial parts are used as traditional medicine in China for the treatment of the common cold, headache, aphtha, rubella, measles, and inflammatory diseases [1, 2]. The chemical and biological investigation of the constituents of M. haplocalyx have been actively studied, as represented by [3–6]. During our previous phytochemical investigation of this plant, we have reported several phenylpropanoids, monoterpenoids, polyphenolic acids, and flavonoids from the aqueous extract of M. haplocalyx. To discover more interesting molecules from M. haplocalyx, a phytochemical investigation was carried out. Our current chemical analysis of the 70% ethanol extract of the aerial parts of M. haplocalyx has led to 19 compouds, including six terpenoid glycosides, which were the representative and potential bioactive chemical constituents of the family Labiatae [7–9], six flavonoids, three phenylpropanoids, two phenolic acids, and two other compounds. The aerial parts of M. haplocalyx (20 kg) were extracted twice with 70% ethanol. The ethanol extract was subjected to Dianion HP 2MGL and SP825 chromatography column (CC) eluted with H2O–MeOH (95:5–5:95). Repeated CC of fractions obtained from the above isolation over silica gel using CHCl3–MeOH–H2O as gradient system, ODS-A, and MCI-gel eluted by H2O–MeOH resulted in the isolation of 19 compounds: 1 (5 mg), 2 (5 mg), 3 (0.7 mg), 4 (3 mg), 5 (3 mg), 6 (6 mg), 7 (2 mg), 8 (6.6 mg), 9 (1.9 mg), 10 (0.8 mg), 11 (6 mg), 12 (5 mg), 13 (5 mg), 14 (20 mg), 15 (3 mg), 16 (2.8 mg), 17 (1.7 mg), 18 (3 mg), 19 (2 mg). The isolated compounds 2, 4, and 6 were obtained for the first time from Labiatae, 1, 3, 5, 7, and 9 were reported for the first time from the genus Mentha, and 8, 11, 16, and 19 were isolated for the first time from this plant. The structures of all 19 compounds were established using spectral data (NMR and MS) and comparison with the literature. Floralquinquenoside C (1), off-white amorphous powder. Its molecular formula was determined as C42H72O15 on the basis of the positive-ion ESI-MS at m/z 839.3 [M + Na]+, together with its 1H and 13C NMR spectral data. 1H NMR spectrum (500 MHz, CD3OD, δ, ppm, J/Hz): 6.12 (1H, d, J = 15.0, H-24), 5.35 (1H, d, J = 7.9, H-1′), 4.83 (1H, m, H-6), 3.97 (1H, t, J = 9.2, H-12), 3.71 (1H, dd, J = 4.8, 11.9, H-3), 2.18 (3H, s, H-28), 0.82, 0.94, 0.95, 0.99, 1.30, 1.54, 1.90 (21H, CH3-19, 30, 18, 29, 21, 27). 13C NMR spectrum (125 MHz, CD3OD, δ, ppm): 138.4 (C-24), 127.3 (C-23), 103.8 (C-1′), 102.8 (C-1′′), 78.3 (C-25), 78.9 (C-3), 78.1 (C-3′), 77.9 (C-5′), 78.6 (C-2′), 75.3 (C-4′′), 74.5 (C-4′), 74.4 (C-6), 74.2 (C-2′′), 74.1 (C-3′′), 73.3 (C-20), 71.7 (C-12), 69.1 (C-5′′), 65.7 (C-6′), 62.8 (C-5), 49.9 (C-9), 49.5 (C-13), 46.2 (C-7), 43.0 (C-8), 41.4 (C-22), 40.7 (C-10), 39.8 (C-4), 39.8 (C-1), 32.9 (C-28), 33.4 (C-11), 31.3 (C-15), 28.9 (C-2), 25.8 (C-27), 25.5 (C-16), 25.2 (C-26), 25.0 (C-21), 20.0 (C-6′′), 19.9 (C-19), 19.1 (C-18), 18.5 (C-29), 18.1 (C-30) [10]. Actinidioionoside (2), white powder. 1H NMR spectrum (500 MHz, CD3OD, δ, ppm, J/Hz): 5.97 (1H, d, J = 15.6, H-7), 5.73 (1H, dd, J = 15.6, 7.2, H-8), 4.32 (1H, d, J = 7.8, H-9), 4.28 (1H, d, J = 7.8, H-1′), 3.86–3.81 (4H, m, H-2′, 3′, 4′, 5′), 3.68–3.62 (2H, m, H-6′), 2.05 (1H, d, J = 1.3, H-4b), 1.95 (1H, d, J = 1.3, H-4a), 1.88–1.74 (2H, m, H-2), 1.25 (3H, d, J = 6.3, H-10), 1.10 (3H, s, H-13), 1.04 (3H, s, H-11), 1.02 (3H, s, H-12). 13C NMR spectrum (125 MHz, CD3OD, δ, ppm): 134.7 (C-8), 132.4 (C-7), 102.6 (C-1′), 78.9 (C-6), 78.8 (C-9), 78.1 (C-5′), 78.0 (C-3′), 77.7 (C-5), 75.4 (C-2′), 71.8 (C-4′), 65.3 (C-3), 62.8 (C-6′), 46.6 (C-2), 45.6 (C-4), 40.8 (C-1), 27.6 (C-13), 27.4 (C-12), 26.2 (C-11), 21.9 (C-10) [11].