The Effects of Drying Techniques on Phytochemical Contents and Biological Activities on Selected Bamboo Leaves
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 nutrien...
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MDPI AG
2022-09-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/27/19/6458 |
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| author | Mohammad Amil Zulhilmi Benjamin Shean Yeaw Ng Fiffy Hanisdah Saikim Nor Azizun Rusdi |
| author_facet | Mohammad Amil Zulhilmi Benjamin Shean Yeaw Ng Fiffy Hanisdah Saikim Nor Azizun Rusdi |
| author_sort | Mohammad Amil Zulhilmi Benjamin |
| collection | DOAJ |
| description | 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, <i>Bambusa multiplex</i>, <i>Bambusa tuldoides</i>, <i>Bambusa vulgaris</i>, <i>Dinochloa sublaevigata</i>, <i>Gigantochloa levis</i>, and <i>Schizostachyum brachycladum</i>. 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 <i>B. vulgaris</i> 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 IC<sub>50</sub> (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 LC<sub>50</sub> (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. |
| first_indexed | 2024-03-09T21:24:48Z |
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| spelling | doaj.art-8cad7b1890b14be4bb6f25ca6f25a2552023-11-23T21:11:45ZengMDPI AGMolecules1420-30492022-09-012719645810.3390/molecules27196458The Effects of Drying Techniques on Phytochemical Contents and Biological Activities on Selected Bamboo LeavesMohammad Amil Zulhilmi Benjamin0Shean Yeaw Ng1Fiffy Hanisdah Saikim2Nor Azizun Rusdi3Institute for Tropical Biology and Conservation, Universiti Malaysia Sabah, Jalan UMS, Kota Kinabalu 88400, Sabah, MalaysiaInstitute for Tropical Biology and Conservation, Universiti Malaysia Sabah, Jalan UMS, Kota Kinabalu 88400, Sabah, MalaysiaInstitute for Tropical Biology and Conservation, Universiti Malaysia Sabah, Jalan UMS, Kota Kinabalu 88400, Sabah, MalaysiaInstitute for Tropical Biology and Conservation, Universiti Malaysia Sabah, Jalan UMS, Kota Kinabalu 88400, Sabah, MalaysiaThe 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, <i>Bambusa multiplex</i>, <i>Bambusa tuldoides</i>, <i>Bambusa vulgaris</i>, <i>Dinochloa sublaevigata</i>, <i>Gigantochloa levis</i>, and <i>Schizostachyum brachycladum</i>. 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 <i>B. vulgaris</i> 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 IC<sub>50</sub> (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 LC<sub>50</sub> (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.https://www.mdpi.com/1420-3049/27/19/6458drying methodsantioxidant activitiesbrine shrimp lethality assayphytochemical contentsbamboo leaves |
| spellingShingle | Mohammad Amil Zulhilmi Benjamin Shean Yeaw Ng Fiffy Hanisdah Saikim Nor Azizun Rusdi The Effects of Drying Techniques on Phytochemical Contents and Biological Activities on Selected Bamboo Leaves Molecules drying methods antioxidant activities brine shrimp lethality assay phytochemical contents bamboo leaves |
| title | The Effects of Drying Techniques on Phytochemical Contents and Biological Activities on Selected Bamboo Leaves |
| title_full | The Effects of Drying Techniques on Phytochemical Contents and Biological Activities on Selected Bamboo Leaves |
| title_fullStr | The Effects of Drying Techniques on Phytochemical Contents and Biological Activities on Selected Bamboo Leaves |
| title_full_unstemmed | The Effects of Drying Techniques on Phytochemical Contents and Biological Activities on Selected Bamboo Leaves |
| title_short | The Effects of Drying Techniques on Phytochemical Contents and Biological Activities on Selected Bamboo Leaves |
| title_sort | effects of drying techniques on phytochemical contents and biological activities on selected bamboo leaves |
| topic | drying methods antioxidant activities brine shrimp lethality assay phytochemical contents bamboo leaves |
| url | https://www.mdpi.com/1420-3049/27/19/6458 |
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