Bioactivity and stability studies of anthocyanin-containing extracts from Garcinia mangostana L. and Etlingera elatior Jack

Anthocyanin-containing extract (ACE) were prepared from the pericarp of Garcinia mangostana L. (mangosteen) and the inflorescence part of Etlingera elatior Jack (torch ginger) by using acidified methanol as extraction solvent. Our present study focuses on the antioxidant and cytotoxic activity and the effect of temperature, light and pH on stability of ACE derived from G. mangostana and E. elatior. The monomeric anthocyanin and total phenolic content in E. elatior was higher (43.42±0.01 mg/L dan 10.07±0.01 gGAE /100 g) compared to G. mangostana (15.03±0.01 mg/L and 3.29±0.01 gGAE/100 g). Both ACE of E. elatior and G. mangostana exhibited free radical scavenger activity, with IC50 value of14.90±1.02 mg/mL and 15.50±0.52 mg/mL, respectively, in 2,2’-diphenyl-1-picrylhydrazyl assay. ACE of E. elatior was also found to be a good reducing and possessed higher absorbance values at concentrations range from 1.25 to 20 mg/mL in FRAP assay. ACE of E. elatior exhibited mild cytotoxicity on human ovarian SKOV-3 cell line with IC50 values of 54.32 ± 4.60 μg/mL. The effects of light and temperature on ACE stability were performed in different environmental conditions, which promote the destabilization of anthocyanin molecules. ACE stability of G. mangostana were less resist to the effect of light but very susceptible to the prolonged effect of heat after 2 h exposure compared to the ACE in E. elatior. The different in pH highly influence the stability of both ACE which can be observed from the decrease in absorbance readings

Simplifed cochlear frequency selectivity measure for sensorineural hearing loss screening: comparison with digit triplet test (DTT) and shortened speech, spatial and qualities of hearing scale (SSQ) questionnaire

Purpose Pure-tone audiometry (PTA) is the gold standard for screening and diagnosis of hearing loss but is not always accessible. This study evaluated a simplified cochlear frequency selectivity (FS) measure as an alternative option to screen for early frequency-specific sensorineural hearing loss (SNHL). Methods FS measures at 1 and 4 kHz center frequencies were obtained using a custom-made software in normal-hearing (NH), slight SNHL and mild-to-moderate SNHL subjects. For comparison, subjects were also assessed with the Malay Digit Triplet Test (DTT) and the shortened Malay Speech, Spatial and Qualities of Hearing Scale (SSQ) questionnaire. Results Compared to DTT and SSQ, the FS measure at 4 kHz was able to distinguish NH from slight and mild-to-moderate SNHL subjects, and was strongly correlated with their thresholds in quiet determined separately in 1-dB step sizes at the similar test frequency. Further analysis with receiver operating characteristic (ROC) curves indicated area under the curve (AUC) of 0.77 and 0.83 for the FS measure at 4 kHz when PTA thresholds of NH subjects were taken as ≤ 15 dB HL and ≤ 20 dB HL, respectively. At the optimal FS cut-off point for 4 kHz, the FS measure had 77.8% sensitivity and 86.7% specificity to detect 20 dB HL hearing loss. Conclusion FS measure was superior to DTT and SSQ questionnaire in detecting early frequency-specific threshold shifts in SNHL subjects, particularly at 4 kHz. This method could be used for screening subjects at risk of noise-induced hearing loss