Extract‐rich in flavonoids from Hibiscus sabdariffa calyces: Optimizing microwave‐assisted extraction method and characterization through LC‐Q‐TOF‐MS analysis

Abstract

Hibiscus sabdariffa comprises calyx which is rich in flavonoids and numerous phytochemical compounds. Nevertheless, the extraction parameters can influence the recoveries of these bioactive compounds. It is then important to investigate the contributing effects of the process parameters and optimized their conditions to achieve higher recovery yield. Hence, this study was carried out to examine the contributing effects of microwave-assisted extraction (MAE) process factors (irradiation time, ethanol concentration, solvent/sample ratio, temperature, and microwave power) on the yield of total flavonoid (TF) contents from H. sabdariffa calyces using one-variable-at-a-time.The significant MAE process parameters were further optimized using Box Behnken design. At the MAE optimal conditions, the extract was analyzed to identify the flavonoid compounds using liquid chromatography-mass spectrometry quadrupole time of flight. An optimum TF content of 94.32 mg QE/g extract from H. sabdariffa calyces was obtained at the following MAE conditions: Irradiation time of 4 min; ethanol concentration of 52% vol/vol; microwave power of 450 W and solvent/sample ratio 15:1 ml/g. Moreover, 95 flavonoid compounds were tentatively identified in the extract at optimized MAE conditions. Thus, these flavonoids can be further isolated in future studies to unveil embedded potentials of H. sabdariffa calyx extract. Practical applicationThe procedure described the microwave-assisted extraction (MAE) which can serve as a guideline for extracting flavonoids from Hibiscus sabdariffa calyx. Moreover, the liquid chromatography-mass spectrometry quadrupole time of flight analysis provided the developed conditions for identifying flavonoids from the calyces. The results obtained suggested the exact MAE conditions to achieve an optimum yield of flavonoids from H. sabdariffa calyces. Most importantly, the tentatively identified flavonoids can further be isolated and purified in future studies to unveil the embedded biological potentials.

A holistic approach for microwave assisted solvent extraction of phenolic compounds from Ficus benghalensis fruits and its phytochemical profiling

“…The phenolic compounds (TPC and TFC) yield elevated from 240 to 331 mg GAE/g and 308 to 403 mg QE/g, respectively, as the power increased from 350 to 420 W and it is shown in Figures 2 and 3. This could be due to the improvement of power which leads to promote the solubility and diffusion of solute components out of the solid matrix (Alara, Abdurahman, Obanijesu, Alara, & Mudalip, 2020; Yingngam, Chiangsom, & Brantner, 2020). Moreover, the elevated pressure occurred due to microwaves inside the cell wall enhances micro explosions which could release the solute (Yingngam & Brantner, 2018).…”

Hibiscus sabdariffa extract protects HT-22 cells from glutamate-induced neurodegeneration by upregulating glutamate transporters and exerts lifespan extension in C. elegans via DAF-16 mediated pathway

“…Ethyl linoleate showed an anti-inflammatory effect by inducing the expression of HO-1 in RAW264.7 cells [59]. Apart from the compounds identified, previous reports using LC-MS analysis have also reported on the presence of various polyphenols with neuroprotective activities including luteolin, myricetin, kaempferol, quercetin, protocatechuic acid, and hibiscus acid [60,61].…”

Microwave-Assisted Extraction of Bioactive Compounds (Review)

“…Extraction involves separating dissolvable substances from non-dissolvable residues using solvent(s); it can be in form of liquid or solid [1]. There are two categories of extraction which are traditional and modern; the former includes Soxhlet, soaking, maceration, ultra-sonication, turbo-fast blending, and solvent permeation; the latter includes ultrasonic-assisted, subcritical, supercritical CO 2 , enzyme-assisted, pressure-assisted, and microwave-assisted methods [2][3][4][5][6]. The traditional methods are mainly associated with an extended time of extraction, destruction of heat-sensitive bioactive compounds, and enormous consumption of solvents [3,7].…”

“…In most cases, the extraction time and microwave power fall within 30 s to 10 min and 25 to 750 W, respectively [17]. Several studies had reported the use of MAE for recovering phenolics from plant samples including bitter leaf, purple fleabane, roselle, tea leaf, vanilla, radix, flax seeds, scent leaf, siam weed, and among others [6,8,9,[18][19][20][21][22].…”