Yuanhang Yao

β-cryptoxanthin is a provitamin A xanthophyll carotenoid that is abundant in human circulation, despite being derived from a relatively limited range of dietary sources, primarily citrus fruits, which contain approximately 0.5–10.0 mg per 100 g fresh weight. Owing to the polarity and the frequent occurrence associated with β-cryptoxanthin as esterified forms in foods, β-cryptoxanthin exhibits relatively high bioaccessibility and bioavailability. This review aims to provide a comprehensive overview of the current evidence regarding the biochemical characteristics, dietary sources, determinants of absorption, and potential health effects of β-cryptoxanthin, with particular emphasis on bone health and several cancer outcomes. Among the health outcomes examined, the evidence is most consistent for a beneficial role in skeletal health. In contrast, associations with cancer are heterogeneous and appear to depend on cancer type and population characteristics; inverse associations have been reported primarily for cancers of the upper aerodigestive tract, whereas most studies show no association with overall cancer incidence or mortality. Nonetheless, further research is required to investigate whether β-cryptoxanthin can be incorporated into evidence-based precision nutrition approaches that account for interindividual variability in metabolism, lifestyle, and disease risk.

This study evaluated the fruits of Forsythia suspensa (Lianqiao), an important economic crop, for the chemical components of its water and ethanol extracts, inhibitory effects on SARS-CoV-2 virus spike protein binding to ACE2, inhibition of ACE2 activity, and capacity to scavenge free radicals. A total of 42 compounds were tentatively identified in the extracts via HPLC-MS/MS analysis. The water extract showed a greater ACE2 inhibition but a weaker inhibition on SARS-CoV-2 spike protein binding to ACE2 than the ethanol extract on a per-botanical-weight-concentration basis. The phenolic content was found to be greater in the water extract at 45.19 mg GAE/g dry botanical weight than in the ethanol extract (6.89 mg GAE/g dry botanical). Furthermore, the water extract had greater scavenging capacities against HO^●, DPPH^●, and ABTS^●+ at 448.48, 66.36, and 121.29 µmol TE/g dry botanical, respectively, as compared to that of the ethanol extract (154.04, 3.55, and 33.83 µmol TE/g dry botanical, respectively). These results warrant further research into, and the development of, the potential COVID-19-preventive applications of Lianqiao and its extracts.

Water and ethanol extracts of dried thyme (Thymus vulgaris) were analyzed for chemical composition, inhibition of the SARS-CoV-2 spike protein-ACE2 interaction, inhibition of ACE2 activity, and free radical scavenging capacity. Thirty-two compounds were identified in water extract (WE) and 27 were identified in ethanol extract (EE) of thyme through HPLC-MS. The WE (33.3 mg/mL) and EE (3.3 mg/mL) of thyme inhibited the spike protein-ACE2 interaction by 82.6 and 86.4%, respectively. The thyme WE at 5 mg/mL inhibited ACE2 activity by 99%, and the EE at 5 mg/mL inhibited ACE2 by 65.8%. Total phenolics were determined to be 38.9 and 8.8 mg of GAE/g in WE and EE, respectively. The HO^• scavenging capacities were 1121.1 and 284.4 μmol of TE/g in WE and EE, respectively. The relative DPPH^• scavenging capacities were 126.3 μmol TE/g in WE and 28.2 μmol TE/g in EE. The ABTS^•+ scavenging capacities were 267.1 μmol TE/g in WE and 96.7 μmol TE/g in EE. The results suggested that the thyme extract could be potentially used to prevent SARS-CoV-2 infection and mitigate the complications from the infection.

This study evaluated the chemical composition of rosemary water extract (RWE) and its influence on mechanisms by which the SARS-CoV-2 virus enters into cells as a potential route for reducing the risk of COVID-19 disease. Compounds in RWE were identified using UHPLC-MS/MS. The inhibitory effect of RWE was then evaluated on binding between the SARS-CoV-2 spike protein (S-protein) and ACE2 and separately on ACE2 activity/availability. Additionally, total phenolic content (TPC) and free radical scavenging capacities of RWE against HO^•, ABTS^•+, and DPPH^• were assessed. Twenty-one compounds were tentatively identified in RWE, of which tuberonic acid hexoside was identified for the first time in rosemary. RWE dose of 33.3 mg of rosemary equivalents (RE)/mL suppressed the interaction between S-protein and ACE2 by 72.9%, while rosmarinic and caffeic acids at 3.3 μmol/mL suppressed the interaction by 36 and 55%, respectively. RWE at 5.0, 2.5, and 0.5 mg of RE/mL inhibited ACE2 activity by 99.5, 94.5, and 68.6%, respectively, while rosmarinic acid at 0.05 and 0.01 μmol/mL reduced ACE2 activity by 31 and 8%, respectively. RWE had a TPC value of 72.5 mg GAE/g. The results provide a mechanistic basis on which rosemary may reduce the risk of SARS-CoV-2 infection and the development of COVID-19.

This letter acknowledges Finsterer and colleagues' insightful comments on pesticide use in fruits and vegetables and impact on eye health. Pesticides can harm eyes through various exposures. Adverse effects occur due to direct entry into ocular tissues, with absorption through eye components. While the potential of organic diets to reduce pesticide exposure is acknowledged, the original paper's cited studies lack clarity on whether organic diet interventions were used. Future systematic reviews comparing organic and nonorganic diets could provide further insights.

Forsythia suspensa (Lianqiao) has long been touted for its anti-viral effects in folklore. Although promising, limited research were conducted to evaluate its potential in defending the severe acute respiratory syndrome coronavirus (SARS-CoV-2). This study evaluated the fruits of Forsythia suspensa (Lianqiao), an important economic crop, for the chemical components of its water and ethanol extracts, along with their inhibitory effects on SARS-CoV-2 spike protein binding to angiotensin-converting enzyme 2 (ACE2), inhibitions of ACE2 activity, and capacities to scavenge the selected free radicals. A total of 42 compounds were tentatively identified in the extracts by HPLC-MS/MS analysis. Both water and ethanol extracts of Lianqiao showed great inhibition of ACE2 activity and the binding affinity between SARS CoV-2 spike protein and ACE2. Furthermore, the water extract had greater scavenging capacities against HO^●, DPPH^● and ABTS^●+ than the ethanol extract. Findings of this research contribute to the knowledge of different extraction solvent systems and support the potential of Lianqiao in reducing the risk of coronavirus infection and alleviating the symptoms after infection.