Ethanolic extracts of South African plants, Buddleja saligna Willd. and Helichrysum odoratissimum (L.) Sweet, as multifunctional ingredients in sunscreen formulations

Show simple item record Twilley, Danielle Moodley, Deveshnee Rolfes, Heidi Moodley, Indres McGaw, Lyndy Joy Madikizela, Balungile Summers, Beverley Raaff, Lee-ann Lategan, Marlize Kgatuke, Lebogang Mabena, Ephraim C. Lall, Namrita 2021-09-09T05:28:48Z 2021-03
dc.description.abstract Exposure to solar ultraviolet (UV) radiation is a major contributing factor to the increasing number of skin cancer cases. Interest has grown to use plant extracts as natural ingredients in cosmetic formulations due to their photoprotective effect, antioxidant and anti-inflammatory activity, as well as other biological activities. The aim of this study was to evaluate the biological activity of two South African plant extracts, Helichrysum odoratissimum (L.) Sweet. and Buddleja saligna Willd., and to successfully incorporate these extracts into sunscreen formulations (o/w emulsions) due to their reported biological activity. Ethanolic extracts were prepared from the leaves and stems of H. odoratissimum and B. saligna and evaluated for their antioxidant activity, mutagenic potential and antiproliferative activity against human dermal fibroblasts (MRHF). The extracts were further characterized using gas chromatography-mass spectrometry (GC-MS). Thereafter, the extracts were incorporated into separate sunscreen formulations to evaluate the in vivo dermal irritancy potential, in vivo sun protection factor, in vitro UVA protection, photostability and long term stability of the formulation, to confirm that by incorporating the extracts, the stability or photoprotective effect of the sunscreen formulation was not reduced and that these formulation were considered safe for topical application. Three separate sunscreen formulations were prepared; the base sunscreen formulation (formulation A), the base sunscreen formulation containing B. saligna (formulation B) and H. odoratissimum (formulation C) respectively. Both extracts showed significant radical scavenging activity using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay with a fifty percent inhibitory concentration (IC50) of 5.13 ± 0.07 and 8.16 ± 0.34 µg/mL for H. odoratissimum and B. saligna respectively. No mutagenic activity was observed when the extracts were tested in the Ames assay using Salmonella typhimurium (TA98 and TA100). The PrestoBlue® cell viability assay was used to determine the antiproliferative activity of the extracts against MRHF cells, both extracts showed an IC50 value >90 µg/mL. Photoprotective activity was measured using in vivo sun protection factor (SPF) test method according to South African (SANS 1557) and International (ISO 24444) standards as well as the in vitro UVA SPF testing procedure (ISO 24443). The SPF results showed that the formulations had broad-spectrum UV protection with SPF values of 15.8±0.41, 16.1±0.66 and 16.0±0.49 and UVAPF values of 6.47±0.06, 6.45±0.06 and 6.47±0.07 for formulation A, B and C respectively. Furthermore, the formulations remained stable under normal and extreme conditions and the plant extracts did not affect the photoprotective effect of the sunscreen formulations and contributed towards the formulations stability. Additionally, each of the formulations were photostable, whereas the formulations with the addition of the extracts showed an incremental increase in photostability when compared to the base formulation. Both these extracts have been previously reported to display antiproliferative activity against skin cancer cell lines (previously published data), with an IC50 value of 31.80 ± 0.35 µg/mL (human malignant melanoma, UCT-MEL-1) for B. saligna and IC50 values of 15.50 ± 0.20 (human epidermoid carcinoma, A431) and 55.50 ± 6.60 µg/mL (human malignant melanoma, A375) for H. odoratissimum, contributing towards the medicinal benefit of using these extracts as ingredients into sunscreen formulations. Therefore, Helichrysum odoratissimum and Buddleja saligna could be considered as useful and viable additives to sunscreen formulations due to their reported biological activity. en_ZA
dc.description.department Chemical Engineering en_ZA
dc.description.department Paraclinical Sciences en_ZA
dc.description.department Plant Production and Soil Science en_ZA
dc.description.embargo 2021-11-01
dc.description.librarian hj2021 en_ZA
dc.description.sponsorship The National Research Foundation of South Africa en_ZA
dc.description.uri en_ZA
dc.identifier.citation Twilley, D., Moodley, D., Rolfes, H. et al. 2021, 'Ethanolic extracts of South African plants, Buddleja saligna Willd. and Helichrysum odoratissimum (L.) Sweet, as multifunctional ingredients in sunscreen formulations', South African Journal of Botany, vol. 137, pp 171-182. en_ZA
dc.identifier.issn 0254-6299 (print)
dc.identifier.issn 1727-9321 (online)
dc.identifier.other 10.1016/j.sajb.2020.10.010
dc.language.iso en en_ZA
dc.publisher Elsevier en_ZA
dc.rights © 2020 SAAB. Published by Elsevier B.V. All rights reserved. Notice : this is the author’s version of a work that was accepted for publication in South African Journal of Botany. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. A definitive version was subsequently published in South African Journal of Botany, vol. 137, pp 171-18 , 2021. doi : 10.1016/j.sajb.2020.10.010. en_ZA
dc.subject South African medicinal plants en_ZA
dc.subject Helichrysum odoratissimum L. (Sweet) en_ZA
dc.subject Buddleja saligna (Willd.) en_ZA
dc.subject Photoprotective activity en_ZA
dc.subject Sun protection factor en_ZA
dc.subject Antioxidant en_ZA
dc.subject Antiproliferative activity en_ZA
dc.subject Dermal irritancy en_ZA
dc.subject Mutagenicity en_ZA
dc.subject Stability en_ZA
dc.subject Gas chromatography-mass spectrometry (GC-MS) en_ZA
dc.title Ethanolic extracts of South African plants, Buddleja saligna Willd. and Helichrysum odoratissimum (L.) Sweet, as multifunctional ingredients in sunscreen formulations en_ZA
dc.type Postprint Article en_ZA

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