Effect of Oven and Microwave Drying on Polyphenols Content and Antioxidant Capacity of Herbal Tea From Strobilanthes Crispus Leaves

Lasano, Nur Fatimah; Rahmat, Asmah; Ramli, Nurul Shazini; Bakar, Mohd Fadzelly Abu

doi:10.22159/ajpcr.2018.v11i6.24660

Cited by 7 publications

(4 citation statements)

References 42 publications

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“…This finding is comparable with others who reported a similar trend of significant higher values of antioxidant activity along with total phenol and flavonoid [39]. Lasano et al [40] indicated a great association of antioxidant activity with TPC and TFC in unfermented Strobilanthes crispa tea. It has also been shown that in vitro antioxidant powers vary according to teas and antioxidant capacity and the content of total phenolics in tea is strongly correlated [23] as phenolic compounds are powerful chain breaking antioxidants that can directly contribute to antioxidative action [41].…”

Section: Discussionsupporting

confidence: 89%

Seasonal Variations in Antioxidant Capacities and Phenolic Contents of Tea Leaf Extracts

JAMIR

Ajungla

2020

Asian J Pharm Clin Res

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Objectives: The objective of the study was to estimate the seasonal variations in the antioxidant capacities, total polyphenol content (TPC), total flavonoid content (TFC), and tannin content (TC) of tea leaf extracts from two different plantation sites. Methods: Samples were collected from two tea gardens in Tuli and Ungma situated at N 26°39’19.3 E 094°39’22.7 and N 26°17’30.6 E 094°28’29.2, respectively, under the Mokokchung district of Nagaland, India. TPC, TFC, and TC from sample extracts were determined using Folin–Ciocalteu reagent, aluminum chloride colorimetric, and Folin–Ciocalteu assay. Apart from these, antioxidant capacities were analyzed using ferric reducing ability of plasma (FRAP) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. Results: The concentrations of total polyphenol, flavonoid, and tannin varied from 552.029±8.079 to 305.647±1.744 mg gallic acid equivalent/g, 238.770±0.508–148.457±1.653 mg catechin equivalent/g, and 26.453±0.485–20.173±0.173 mg tannic acid equivalent/g, respectively. FRAP and DPPH assay displayed value ranging from 2.564±0.023 to 1.074±0.023 mmol Fe(II) equivalent/g and 3.612±0.053–2.076±0.028 mmol Trolox equivalent/g. Significant seasonal variations in concentrations of these compounds were observed and a positive correlation between antioxidant capacities and phenolics of tea leaf extracts was established. Conclusion: Tea (Camellia sinensis (L.) O. Kuntze) has been regarded as a plant of immense medicinal and therapeutic value since time immemorial. The tea leaf extracts analyzed in this study gave high TPC, TFC, and TC, as well as high antioxidant activity in terms of DPPH and FRAP value. Studying such properties in tea leaves contributes more to our understandings of health benefit potentials in tea leaves and the quality of tea leaves on the basis of seasons and sites where they are planted.

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Section: Discussionsupporting

confidence: 89%

Seasonal Variations in Antioxidant Capacities and Phenolic Contents of Tea Leaf Extracts

JAMIR

Ajungla

2020

Asian J Pharm Clin Res

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“…Nevertheless, the microwave-dried B. tuldoides and B. vulgaris specimens in the current study recorded the highest FRAP yield. Similarly, Lasano et al [ 41 ] recommended microwaving fermented and unfermented Strobilanthes crispus tea to obtain preferable antioxidant capacities, including FRAP and DPPH. The antioxidant index proposed by the report might also be employed as a new marker in determining the optimal drying method for varying food products [ 41 ].…”

Section: Resultsmentioning

confidence: 99%

The Effects of Drying Techniques on Phytochemical Contents and Biological Activities on Selected Bamboo Leaves

Benjamin

Saikim

et al. 2022

Molecules

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The therapeutic potential of bamboos has acquired global attention. Nonetheless, the biological activities of the plants are rarely considered due to limited available references in Sabah, Malaysia. Furthermore, the drying technique could significantly affect the retention and degradation of nutrients in bamboos. Consequently, the current study investigated five drying methods, namely, sun, shade, microwave, oven, and freeze-drying, of the leaves of six bamboo species, Bambusa multiplex, Bambusa tuldoides, Bambusa vulgaris, Dinochloa sublaevigata, Gigantochloa levis, and Schizostachyum brachycladum. The infused bamboo leaves extracts were analysed for their total phenolic content (TPC) and total flavonoid content (TFC). The antioxidant activities of the samples were determined via the 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), and ferric reducing antioxidant power (FRAP) assays, whereas their toxicities were evaluated through the brine shrimp lethality assay (BSLA). The chemical constituents of the samples were determined using liquid chromatography–tandem mass spectrometry (LC-MS/MS). The freeze-drying method exhibited the highest phytochemical contents and antioxidant activity yield, excluding the B. vulgaris sample, in which the microwave-dried sample recorded the most antioxidant and phytochemical levels. The TPC and TFC results were within the 2.69 ± 0.01–12.59 ± 0.09 mg gallic acid equivalent (GAE)/g and 0.77 ± 0.01–2.12 ± 0.01 mg quercetin equivalent (QE)/g ranges, respectively. The DPPH and ABTS IC50 (half-maximal inhibitory concentration) were 2.92 ± 0.01–4.73 ± 0.02 and 1.89–0.01 to 3.47 ± 0.00 µg/mL, respectively, indicating high radical scavenging activities. The FRAP values differed significantly between the drying methods, within the 6.40 ± 0.12–36.65 ± 0.09 mg Trolox equivalent (TE)/g range. The phytochemical contents and antioxidant capacities exhibited a moderate correlation, revealing that the TPC and TFC were slightly responsible for the antioxidant activities. The toxicity assessment of the bamboo extracts in the current study demonstrated no toxicity against the BSLA based on the LC50 (lethal concentration 50) analysis at >1000 µg/mL. LC-MS analysis showed that alkaloid and pharmaceutical compounds influence antioxidant activities, as found in previous studies. The acquired information might aid in the development of bamboo leaves as functional food items, such as bamboo tea. They could also be investigated for their medicinal ingredients that can be used in the discovery of potential drugs.

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“…In another study, microwave-dried blueberry leaves showed a higher TPC than oven-dried leaf samples [21]. The highest TPC was recorded in the Strobilanthes crispus tea leaves developed from microwave-dried leaves [22]. On the contrary, the total phenolic content of date fruit flesh decreased after microwave and conventional oven drying compared to the control sample [23].…”

Section: Total Phenolic Content Of Leptadenia Pyrotechnica Stemmentioning

confidence: 92%

Effect of Microwave and Conventional Heat Treatment on Total Phenolic Compounds, HPLC Phenolic Profile, and Antioxidant Activity of Leptadenia pyrotechnica (Forssk.) Decne Stem

Alkaltham,

Hayat,

Salamatullah

et al. 2023

Applied Sciences

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Leptadenia pyrotechnica is considered a wild herb used to enhance the palatability of food, particularly in the Gulf region. The effect of microwave (5, 8, and 10 min at 900 W) and hot-air heating (60, 120, and 180 min at 100 °C) on the phenolic compounds and antioxidants of L. pyrotechnica stems was investigated. The results showed that microwave heating gave high values of the total phenolic content (TPC), total flavonoid content (TFC), and antioxidant properties, while the control sample was inferior in all these attributes. Moreover, microwave heating, particularly for 8 min, produced the highest TPC, TFC, and DPPH values (significant at p < 0.05) and reduced power in the L. pyrotechnica stem. However, prolonging the heating time caused adverse effects on the bioactive potential of the samples. The HPLC analysis indicates that both processes caused a significant increment in the phenolic compounds of the sample. Tannic acid, vanillin, and acetyl salicylic acid were found to be higher in the microwaved-treated samples than in those heated with hot air. The tannic acid was found to be high after microwave heating for 8 min at 116.06 mg/100 g, while the higher value of acetylsalicylic acid 119.08 mg/100 g was observed after microwave heating for 5 min. The partial least regression (PLS) validation model revealed that microwave heating, particularly at an 8 min application time, offered better results, and owing to its short processing time, which might be adopted for heating the L. pyrotechnica stems in the food industry, and it can be useful for preparing functional foods.

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Effect of Oven and Microwave Drying on Polyphenols Content and Antioxidant Capacity of Herbal Tea From Strobilanthes Crispus Leaves

Cited by 7 publications

References 42 publications

Seasonal Variations in Antioxidant Capacities and Phenolic Contents of Tea Leaf Extracts

Seasonal Variations in Antioxidant Capacities and Phenolic Contents of Tea Leaf Extracts

The Effects of Drying Techniques on Phytochemical Contents and Biological Activities on Selected Bamboo Leaves

Effect of Microwave and Conventional Heat Treatment on Total Phenolic Compounds, HPLC Phenolic Profile, and Antioxidant Activity of Leptadenia pyrotechnica (Forssk.) Decne Stem

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