Studies on Cytotoxic Activity against HepG-2 Cells of Naphthoquinones from Green Walnut Husks of Juglans mandshurica Maxim

Abstract

Twenty-seven naphthoquinones and their derivatives, including four new naphthalenyl glucosides and twenty-three known compounds, were isolated from green walnut husks, which came from Juglans mandshurica Maxim. The structures of four new naphthalenyl glucosides were elucidated based on extensive spectroscopic analyses. All of these compounds were evaluated for their cytotoxic activities against the growth of human cancer cells lines HepG-2 by MTT [3-(4,5-dimethylthiazo l-2-yl)-2,5 diphenyl tetrazolium bromide] assay. The results were shown that most naphthoquinones in an aglycone form exhibited better cytotoxicity in vitro than naphthalenyl glucosides with IC50 values in the range of 7.33-88.23 μM. Meanwhile, preliminary structure-activity relationships for these compounds were discussed.

Chemical Constituents of the Ethyl Acetate Extract from Diaphragma juglandis Fructus and Their Inhibitory Activity on Nitric Oxide Production In Vitro

“…Compound 11 (peak 11 in Figure 2 B): ESI-MS ( m / z ): 163 [M + H] + , molecular formula C 10 H 10 O 2 , M = 162; 1 H-NMR (CD 3 OD- d 6 , 600 MHz) δ: 2.65 (1H, ddd, J = 5.4, 2.4, 5.4 Hz, H-2), 2.88 (1H, ddd, J = 3.0, 6.0, 3.0 Hz, H-2), 2.15 (1H, m, H-3), 2.38 (1H, m, H-3), 4.94 (1H, dd, J = 4.2, 4.2 Hz, H-4), 7.65 (2H, m, H-5, 6), 7.44 (1H, m, H-7), 7.97 (1H, d, J = 7.8 Hz, H-8); 13 C-NMR (CD 3 OD- d 6 , 150 MHz) δ: 198.5 (C-1), 146.5 (C-10), 133.8 (C-6), 130.9 (C-9), 127.6 (C-8), 127.1 (C-7), 126.2 (C-5), 66.9 (C-4), 34.9 (C-2), 31.7 (C-3). Comparing the above data with the literature [ 32 ], compound 11 was identified as (4 S )-4-hydroxy-1-tetralone.…”

Hydroethanolic extract of Juglans regia L. green husks: A source of bioactive phytochemicals

“…Peaks 4, 13 and 16 correspond to naphthalene derivatives. This group of molecules was already identified in J. mandshurica fruits (Jin-Hai et al, 2018), husks (Jin-Hai et al, 2018;Zhou et al, 2015) and branches (Wang et al, 2017). As with tetralone derivatives, natural naphthalene also occurs with hydroxyl, hexosyl and hydroxybenzoyl substitutions (Sun et al, 2012).…”

“…(Du et al, 2014;Li et al, 2013Li et al, , 2008aLiu et al, 2010;Talapatra et al, 1988;Wang et al, 2017). Particularly, the tetralone derivatives found in green husks of J. regia usually occur as hydroxyl, hexosyl and hydroxybenzoyl derivatives, with several isomeric alternatives (Zhou et al, 2015). Wang et al (2017), the compounds were identified as tetralone galloyl hexoside derivatives, specifically, dihydroxytetralone galloyl hexoside isomers (peaks 8 and 9) and trihydroxytetralone galloyl hexoside (peak 10).…”

“…Nevertheless, the cytotoxic effect of pure isolated compounds from Juglans mandshurica Maxim extracts was evaluated for HepG2 cells (Yang et al, 2019;Zhou et al, 2015). According to Zhou et al (2015), lower IC 50 values were found for naphthoquinone derivatives than the ones obtained for tetralone, and the non-glycosylated forms were more active against the HepG2 cells than the glycosylated ones: dihydroxynaphthoquinone isomers (7.33 ± 0.52 μM to 15.37 ± 1.63 μM) < dihydroxy tetralone (regiolone: 56.87 ± 4.27 μM) < trihydroxy naphthoquinone hexoside isomers (78.61 ± 2.38 μM to 83.32 ± 4.54 μM), while dihydroxyand trihydroxytetralone hexoside isomers were not active against the cell culture. Similar results were found for regiolone in Juglans cathayensis Dode samples against the same cell line (42.56 μM) (Li et al, 2008b).…”

“…To assist the development of new applications in the food, pharmaceutical, and cosmetic areas, among others, it is important to have a detailed characterization of the phytochemical profile of the extracts and, also, of their bioactivity, as this by-product is a source of molecules of potential pharmaceutical interest (Alshatwi et al, 2012;Bagheri et al, 2012;Jahanban-Esfahlan et al, 2019;Oliveira et al, 2008;Sharma et al, 2013;Soto-Maldonado et al, 2019;Zhou et al, 2015).…”