New Insights on Acanthus ebracteatus Vahl: UPLC-ESI-QTOF-MS Profile, Antioxidant, Antimicrobial and Anticancer Activities

Abstract

This study investigated the antioxidant, antimicrobial, anticancer, and phytochemical profiling of extracts from the leaves and stem/root of Acanthus ebracteatus (AE). The total phenolic content (TPC), total flavonoid content (TFC), 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) radical-scavenging activity, 2, 2′-azino-Bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical-scavenging activity, metal chelating activities (MCA), ferric reducing antioxidant power (FRAP) and oxygen radical antioxidant capacity (ORAC) were used for antioxidant assessment. The ethanolic extracts of the leaves (AEL-nor) and stem/root (AEWP-nor) without chlorophyll removal and those with chlorophyll removal, using sedimentation process (AEL-sed and AEWP-sed), were prepared. Generally, AEL-sed showed the highest antioxidant activity (FRAP: 1113.2 µmol TE/g; ORAC: 11.52 µmol TE/g; MCA: 47.83 µmol EDTA/g; ABTS 67.73 µmol TE/g; DPPH 498.8 µmol TE/g; TPC: 140.50 mg/GAE g and TFC: 110.40 mg/CE g) compared with other extracts. Likewise, AEL-sed also showed the highest bacteriostatic (MIC) and bactericidal (MBC) effects, as well as the highest anticancer and antiproliferative activity against oral squamous carcinoma (CLS-354/WT) cells. UPLC-ESI-QTOF/MS analysis of AEL-sed and AEWP-sed tentatively identified several bioactive compounds in the extracts, including flavonoids, phenols, iridoids, and nucleosides. Our results provide a potentially valuable application for A. ebracteatus, especially in further exploration of the plant in oxidative stress-related disorders, as well as the application of the plant as potential nutraceuticals and cosmeceuticals.

Anticancer effects of Rhinacanthus nasutus and Acanthus ebracteatus extracts against human cervical cancer cells

“…. Likewise, TPC (13.30 mg GAE/g DW) and TFC (22.74 mg RE/g DW) values of AE were markedly lower than those in a previous work, TPC of 138.20 mg GAE/g and TFC of 107.60 mg CE/g dry extract (Olatunji et al, 2022). The differences in antioxidant capacity and bioactive content between AE in this work and AE in a recent report may lie in different solvents used for extraction, ages of plants, growth conditions and also their origins.…”

“…The antioxidant activities of RN and AE leaf ethyl acetate extracts were similar based on DPPH and FRAP assays (Table 1). DPPH value (4.05 mg TE/g DW) of AE was much lower than that of leaves of AE (448.10 µmol TE/g dry extract) collected from Surat Thani Province, Thailand (southern part of the country) and extracted by 70% ethanol using a maceration method (Olatunji et al, 2022). .…”

“…Based on their HPLC results, caffeic acid, dihydroferulic acid 4-O-glucuronide, 4-glucogallic acid, chlorogenic acid, kelampayoside A and hydrojuglone glucoside were tentatively identified in AE leaf ethanolic extract (Olatunji et al, 2022). In addition, aliphatic alcohol, phenolic glycosides, aliphatic glycosides, terpenes, flavonoids, megastigmane glycosides, and lignan glycosides have all been documented to be present in AE in the prior investigation (Prasansuklab and Tencomnao, 2018).…”

“…The extract of A. ebracteatus using hot water halted the development and cancers of cell-implanted nude mice with cervical cancer (Mahasiripanth et al, 2012). The recent study showed that AE leaf ethanolic extract with chlorophyll removal using sedimentation process contained dihydroferulic acid 4-O-glucuronide, caffeic acid, 4-glucogallic acid, chlorogenic acid, kelampayoside A and hydrojuglone glucoside (Olatunji et al, 2022). These bioactive compounds are thought to contribute to its antioxidant activities (the ferric reducing antioxidant power (FRAP): 1113.2 µmol Trolox Equivalent (TE)/g and and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging 498.8 µmol TE/g) (Olatunji et al, 2022).…”

“…The recent study showed that AE leaf ethanolic extract with chlorophyll removal using sedimentation process contained dihydroferulic acid 4-O-glucuronide, caffeic acid, 4-glucogallic acid, chlorogenic acid, kelampayoside A and hydrojuglone glucoside (Olatunji et al, 2022). These bioactive compounds are thought to contribute to its antioxidant activities (the ferric reducing antioxidant power (FRAP): 1113.2 µmol Trolox Equivalent (TE)/g and and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging 498.8 µmol TE/g) (Olatunji et al, 2022). Previously, AE protein hydrolysates were shown to exhibit anticancer activity towards skin cancer cell A431 by inducing apoptosis through increased RelA (p65) and Cyclin D1 protein levels (Khamwut et al, 2019).…”