HPLC Profile of Longan (cv. Shixia) Pericarp-Sourced Phenolics and Their Antioxidant and Cytotoxic Effects

Abstract

Longan (Dimocarpus longan Lour.) pericarp, the main by-product of aril and pulp processing, is abundant in phenolic compounds and worthy of further utilization. The present work firstly reported HPLC analysis and in vitro antioxidant evaluation of longan (cv. Shixia) pericarp-derived phenolics (LPPs), the purified longan pericarp extract (LPE), as well as their cytotoxic effect on lung cancer cell line, A549. The results indicated that the purified LPE had significant amounts of phenolics, with content of 57.8 ± 0.6 mg of gallic acid equivalents per gram of dry longan pericarp (mg GAE·g−1 DLP), which consisted of six phenolic compounds (A–F), including protocatechuic acid (A), isoscopoletin (B), quercetin (C), ellagic acid (D), corilagin (E), and proanthocyanidins C1 (F). Antioxidant assays showed that LPPs (10 μM) and LPE (1.0 mg·mL−1) had certain antioxidant activities, in which corilagin (E) possessed the best DPPH radical scavenging rate 71.8 ± 0.5% and •OH inhibition rate 75.9 ± 0.3%, and protocatechuic acid (A) exhibited the strongest Fe2+ chelating ability 36.4 ± 0.7%. In vitro cytotoxic tests suggested that LPPs had different effect on A549 cell line, in which corilagin (E) exhibited potent cytotoxicity with an IC50 value of 28.8 ± 1.2 μM. These findings were further confirmed by cell staining experiments.

Corilagin in Cancer: A Critical Evaluation of Anticancer Activities and Molecular Mechanisms

“…Recently, Bai et al [30] reported the cytotoxic effect of longan ( Dimocarpus longan Lour.) pericarp extract against the A549 lung cancer cell line in vitro.…”

“…Corilagin (β-1- O -galloyl-3,6-( R )-hexahydroxydiphenoyl- d -glucose) is a natural ellagitannin (ET) found in a wide range of plants. In recent years, corilagin has been documented to possess many biological and pharmacological attributes, such as antioxidant [21], anti-inflammatory [22], hepatoprotective [23], antimicrobial [24], antihypertensive [25], antidiabetic [21,26], and antitumor activities [27,28,29,30]. It inhibited reverse transcriptase activity of RNA tumor viruses and possessed significant antistaphylococcal activity (MIC 25 μg/mL) [31].…”

Pericarp and seed of litchi and longan fruits: constituent, extraction, bioactive activity, and potential utilization

“…Table 3 presents the major phenolic compounds in ripe longan pericarps. The major phenolic compounds consisted of gallic acid, quercetin, corilagin, ellagic acid and its conjugates, (−)-epicatechin, 4-O-methylgallic acid, flavone glycosides, glycosides of quercetin and kaempferol, protocatechuic acid, isoscopoletin, and proanthocyanidins C1 (Sun et al, 2007;Yang et al, 2011;Bai et al, 2019). The phenolic compounds present in longan pericarps were similar to those in litchi pericarps (Table 1), suggesting similar bioactive activities.…”

“…The flavonoids present in ripe litchi pericarp include mainly flavonols and anthocyanins. The flavonols identified in ripe litchi pericarps were (−)-epicatechin, (−)-epigallocatechin, procyanidin B2, procyanidin B4, (+)-catechin, and procyanidin B1, whereas the important anthocyanins were identified as cyanidin-3-rutinoside, cyanidin-3-glucoside, quercetin-3-rutinoside, and quercetin-3-glucoside (Sarni-Manchado et al, 2000;Zhao et al, 2006;Bai et al, 2019). A novel compound, namely methylene-linked flavan-3-ol dimer, bis(8-epicatechinyl) methane, was also reported by Ma et al (2014b), together with eight compounds, dehydrodiepicatechin A, proanthocyanidin A1, proanthocyanidin A2, 8-(2-pyrrolidinone-…”

The Antioxidant Capacities of Natural Products 2019

“…sachalinensis and Reynoutria x bohemica [13], fruits of Lycium barbarum L. [14]), the pericarp of Dimocarpus longan Lour. [15], the resin of the tree species Croton lechleri (Müll. Arg) [16] and a herbal standardized product containing an extract of persimmon leaves [17].…”