Tzu-Cheng Chang

Multiple photostabilization actions of heartwood extract from Acacia confusa

Compared to toxic and carcinogenic synthetic photostabilizers, application of plant phenolics as natural photostabilizers is more environmentally friendly. Previous works demonstrated the heartwood extract (HWE) of Acacia confusa has the potential to be a natural wood photostabilizer. However, its exact photostabilities and wood photoprotection abilities are not fully understood. This study aimed to illustrate the photostabilities of the HWE on wood and to recognize the effective components in HWE. The results obtained from the wood photoprotection test and photostability analyses revealed that HWE and its fractions possessed wood photoprotection abilities to retard lignin photodegradation, especially HWE and its EtOAc fraction, due to the abundant catecholic flavonoids endowing the multiple photostabilities, including UVA absorptivity, singlet oxygen quenching ability and phenoxyl radical scavenging efficacy. In addition, the photostability-guided isolation method was successively established for investigating the multiple photostabilization actions of HWE. Accordingly, this method can be applied as the standard procedure for isolating photostabilizers from plant secondary metabolites.

Characteristic aroma-active compounds of floral scent in situ from Barringtonia racemosa and their dynamic emission rates.

Barringtonia racemosa is a nocturnal flowering plant. Information on its floral volatiles and the dynamic emission profiles was very limited. In this study, the floral volatiles of B. racemosa were monitored hourly during its florescence via detached and in situ collection for the first time. The dynamic odor activity value (OAV) was calculated to elucidate the active aroma components of floral scent. Results of compositional analyses showed that the predominant floral volatiles were linalool and phenylacetaldehyde. Their emission started around 8:00 p.m., and the peak emissions were 20541 and 18234 ng h(-1) flower(-1), respectively, during 10:00 p.m.-2:00 a.m. Results from dynamic OAV profiling revealed that linalool (409 min(-1)) and phenylacetaldehyde (547 min(-1)) had higher OAVs than other components (<10 min(-1)), indicating that linalool and phenylacetaldehyde contributed mainly to the floral scent with a strong, sweet, and pleasant aroma.

Wood photostabilization roles of the condensed tannins and flavonoids from the EtOAc fraction in the heartwood extract of Acacia confusa

Lignin, one of the three major components in wood, can absorb UV light and react with 1O2, leading to wood photodegradation. Previous studies demonstrated the ethyl acetate (EtOAc) fraction of the heartwood extract in Acacia confusa (AcHW) has good photostabilities to prevent photodegradation of the wood. However, these effective constituents have different structural characteristics and may affect their photostabilities and protection efficacies on wood which need to be clarified. This study analyzed the polyphenolic contents, chemical constituents and photostabilities of the six subfractions (EA1–EA6) which successively fractioned from the EtOAc fraction in AcHW by the colorimetric methods, UV/Vis spectrophotometry and high-performance liquid chromatography and evaluated the wood photoprotection abilities of these treatments. The results showed the more flavones and flavonols contained in the subfractions, the better the UVA absorptivity was. Besides, the catecholic-condensed tannins and flavonoids in these subfractions also provide good 1O2 quenching abilities and phenoxyl radical scavenging abilities. Advanced results also established in these subfractions, melanoxetin, transilitin, 7,3′,4′-trihydroxy-3-methoxyflavone, 7,8,3′-trihydroxy-3,4′-dimethoxyflavone (flavonols), 7,8,3′,4′-tetrahydroxyflavone, 7,3′,4′-trihydroxyflavone, 7,3′,4′-trihydroxy-5-methoxyflavone (flavones) and okanin (chalcone) can absorb the energy of UVA light; the condensed tannins, 3,4-dihydroxybenzoic acid (phenolic acid), melacacidin-based oligomers, melacacidin, 4-O-methylmelacacidin, 4′-O-methylmelacacidin (melacacidin-based flavanols), 3,7,8,3′,4′-pentahydroxyflavanone (flavanonol), 7,8,3′,4′-tetrahydroxyflavanone (flavanone), the flavones, flavonols and chalcone can suppress the phenoxyl radicals; the condensed tannins, melacacidin-based oligomers and the flavonoids can quench 1O2. Hence, the photostability of extract-free wood slices treated with these effective constituents was consequently enhanced. In summary, these results clearly demonstrated the multiple wood photoprotection actions of these effective constituents and their potential as natural wood photostabilizers.

A review of antioxidant and pharmacological properties of phenolic compounds in Acacia confusa

In the present review article, the phytochemical, antioxidant and pharmacological studies are congregated and summarized concerning the current knowledge of the phenolic compounds of a traditional medical plant Acacia confusa in Taiwan. This plant is native to Taiwan and South-East Asia. It possesses major pharmacological activities, including antioxidant and radical scavenging activity, hepatoprotective effect, xanthine oxidase inhibition, semicarbazide-sensitive amine oxidase inhibition, angiotensin I converting enzyme inhibition, antihyperuricemic effect and anti-inflammatory activity. Phenolic compounds, especially flavonoids, flavonol glycoside and phenolic acid derivatives, are the main phytochemical compounds isolated from different plant parts of A. confusa. Recent interest in this species has focused on pharmacological investigations of the phytochemicals which exhibit potent antioxidant activity based on the multiple phenolic functionalities. The consequence of this review will further extend the potential applications of this plant and offer persuasive support to its future use in the fields of clinical medicine and health functional food.

Erratum to: Exploitation of Acacia confusa heartwood extract as natural photostabilizers

Heartwood extracts of Acacia confusa (HEAc) were proven to have the capability of ameliorating wood photostability. However, the efficacy of photostability compared with that of commercial photostabilizers was unknown. The aim of this study was to examine whether HEAc can be used as commercial photostabilizers. Comparison was made among commercially available photostabilizers, UV absorber (Eversorb 80, EV80) and hindered amine light stabilizer (Eversorb 93, EV93). Photostability of wood slices soaked in 1, 5 and 10 % HEAc or 1 % commercial photostabilizers (EV80 or EV93) solutions was evaluated. The discoloration of 5 and 10 % HEAc-treated specimens was significantly reduced after UV irradiation. Furthermore, lignin degradation and carbonyl formation were concurrently inhibited by 5 and 10 % HEAc treatments after UV irradiation. Interestingly, 1 % HEAc treatment showed similar effectiveness compared with EV80 treatment, while 5 and 10 % HEAc treatments showed better effectiveness than EV80 treatment. HEAc can absorb UV light and quench radicals; hence, wood photodegradation was consequently prevented. These results revealed that HEAc has great potential to be developed as a natural photostabilizer.