Possible Use of Phytochemicals for Recovery from COVID-19-Induced Anosmia and Ageusia

Koyama, Sachiko; Kondo, Kenji; Ueha, Rumi; Kashiwadani, Hideki; Heinbockel, Thomas

doi:10.3390/ijms22168912

Cited by 51 publications

(57 citation statements)

References 480 publications

(590 reference statements)

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“…Due to its therapeutic uses, carnation is nominated as a candidate for the management of COVID-19. [27][28][29][30] During the COVID-19 pandemic, the consumption of carnation as an additive to food or drink to relieve throat pain has increased. 31 A randomized clinical trial of a blend that contains carnation buds demonstrated a boost in energy levels among post-COVID-19 female patients.…”

Section: Discussionmentioning

confidence: 99%

Effect of natural products use prior to infection with COVID-19 on disease severity and hospitalization: A self-reported cross-sectional survey study

et al. 2022

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Background: Managing coronavirus disease 2019 (COVID-19) using available resources is essential to reduce the health burden of disease. The severity of COVID-19 is affected by nutritional status. In this study the effect of natural product use prior to infection with COVID-19 on disease severity and hospitalization was explored. Methods: This was a cross-sectional study. Between March and July 2021, a self-administered survey was conducted in Jordan. Individuals who recovered from COVID-19 and were ≥18 years old were the study population. Study measures included the use of natural products, COVID-19 severity, and hospitalization status. A multivariate regression model was used for statistical analysis. Results: The mean age (mean ± SD) of the study sample (n=2,148) was 40.25 ± 15.58 years old. Multivariate logistic regression showed that the regular intake of carnation (OR [0.56], CI [0.37–0.85]), onion (OR [0.69], CI [0.52–0.92]), lemon (OR [0.68], CI [0.51–0.90]), and citrus fruits (OR [0.66], CI [0.50–0.89]) before infection were associated with a substantial reduction in COVID-19 severity (P<0.01). Also, the consumption of carnation (OR [0.55], CI [0.34–0.88]), lemon (OR [0.57], CI [0.42–0.78]), and citrus fruits (OR [0.61], CI [0.44–0.84]) were associated with a significant decrease in the frequency of COVID-19-induced hospitalization (P<0.01). Conclusions: Regular consumption of carnation, lemon, and citrus fruits before infection was associated with better outcomes for COVID-19. Studies on other populations are required to confirm these findings.

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Section: Discussionmentioning

confidence: 99%

Effect of natural products use prior to infection with COVID-19 on disease severity and hospitalization: A self-reported cross-sectional survey study

et al. 2022

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“…Indeed, flavonoids are well-known for their diverse antiviral effects, and numerous studies have also examined their effect on SARS-CoV-2. Some of these approaches are to increase their bioavailability, and thus, improve their therapeutic efficacy (Ngwa et al, 2020) while others explore the possible use of flavonoids on recovery from COVID-19-Induced anosmia and ageusia (Koyama et al, 2021).…”

Section: Discussionmentioning

confidence: 99%

Antiviral Effects of Some Flavonoids on SARS-CoV-2

Kirmizibekmez

Altintaş²,

Arslan³

et al. 2021

Turkish Journal of Science and Health

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Covid-19 disease caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is a global epidemic that affects millions of lives. To date, there is no definitive cure for the disease and global vaccination efforts with newly produced vaccines will take years to complete. In silico studies have suggested that different flavonoids play an antiviral role against SARS-CoV-2. In this study, based on in silico findings, we examined the in vitro effects of four promising flavonoids, hesperidin, oleuropein, epigallocatechin gallate (EGCG), and myricetin. Material and Methods: Hesperidin, oleuropein, EGCG, and myricetin have been extracted from natural plant sources and purified by using liquid chromatography (LC). Analyses of the cell toxicity and antiviral activity of these four flavonoids at different concentrations against SARS-CoV-2 were done. Results: Our results show that CC50 values for EGCG, hesperidin, myricetin and oleuropein are 38 μg/ml, 25 μg/ml, >200 μg/ml and >200 μg/ml, respectively. In addition, in our hands, neither of the flavonoids we examined has antiviral effects against Sars-CoV-2 virus-infected Vero E6 cells. Our data revealed that all flavonoids we tested have Inhibitory Concentration 50 (IC50) value >200 μg/ml. Conclusion: Our results using the SARS-CoV-2 infected Vero E6 cell model were found to contradict previous in silico findings, and these flavonoids were found to have no antiviral effects in vitro. Studies investigating flavonoids' antiviral activity on SARS-CoV-2 should be directed to those other than oleuropein, hesperidin, EGCG, and myricetin.

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“…It was among the major constituents in the essential oil from lemon leaf in a study by Klimek-Szczykutowicz et al (2020) . Lemon contains many chemical compounds with anti-inflammatory effects: β -caryophyllene, geraniol, limonene, linalool, myrcene, α -pinene, β -pinene, (E)- β -ocimene, sabinene, γ -terpinene, and terpinen-4-ol ( Koyama et al, 2021 for review). The high percentage of limonene suggests that the anti-inflammatory effects could be mediated mainly by limonene, but the large number of chemical constituents with anti-inflammatory effects in lemon also suggests the possibility of synergetic effects by different chemical compounds through the activations of separate receptors and channels.…”

Section: Chemical Constituents Of the Essential Oils Used In Olfactor...mentioning

confidence: 99%

“…Therefore, we propose that it is important to test other combinations of essential oils, especially the combinations of essential oils with chemical constituents with anti-inflammatory effects and with binding affinity to SARS-CoV-2. For example, bitter orange, cinnamon, cypress, elderberry, geranium, lavender, lemongrass, licorice, mint, oregano, paper mulberry, peppermint, summer savory, tea tree, tea plant, thyme, and turmeric contain chemical constituents with binding affinity to SARS-CoV-2 as well as these with anti-inflammatory effects ( Koyama et al, 2021 ). There are two major targets that the binding takes place.…”

Section: Chemical Constituents Of the Essential Oils Used In Olfactor...mentioning

confidence: 99%

“…The phytochemical compounds that possess binding affinity with the proteases are for example, curcumin, cyclocurcumin, (-)-epicatechin, epigallocatechin-3-gallate, kazinol J. The phytochemical compounds that possess binding affinity with the RBD of S-protein are, for example, anethole, carvacrol, cinnamaldehyde (E)-cinnamyl acetate, 1-menthol, 4-terpineol, thymol ( Koyama et al, 2021 ). These differences the target region where binding takes place can generate differences in the effects.…”

Section: Chemical Constituents Of the Essential Oils Used In Olfactor...mentioning

confidence: 99%

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Chemical Constituents of Essential Oils Used in Olfactory Training: Focus on COVID-19 Induced Olfactory Dysfunction

Koyama

Heinbockel

2022

Front. Pharmacol.

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The recent increase in the number of patients with post-viral olfactory dysfunction (PVOD) following the outbreak of COVID-19 has raised the general interest in and concern about olfactory dysfunction. At present, no clear method of treatment for PVOD has been established. Currently the most well-known method to improve the symptoms of olfactory dysfunction is “olfactory training” using essential oils. The essential oils used in olfactory training typically include rose, lemon, clove, and eucalyptus, which were selected based on the odor prism hypothesis proposed by Hans Henning in 1916. He classified odors based on six primary categories or dimensions and suggested that any olfactory stimulus fits into his smell prism, a three-dimensional space. The term “olfactory training” has been used based on the concept of training olfactory sensory neurons to relearn and distinguish olfactory stimuli. However, other mechanisms might contribute to how olfactory training can improve the recovery of the olfactory sense. Possibly, the essential oils contain chemical constituents with bioactive properties that facilitate the recovery of the olfactory sense by suppressing inflammation and enhancing regeneration. In this review, we summarize the chemical constituents of the essential oils of rose, lemon, clove, and eucalyptus and raise the possibility that the chemical constituents with bioactive properties are involved in improving the symptoms of olfactory dysfunction. We also propose that other essential oils that contain chemical constituents with anti-inflammatory effects and have binding affinity with SARS-CoV-2 can be new candidates to test their efficiencies in facilitating the recovery.

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Possible Use of Phytochemicals for Recovery from COVID-19-Induced Anosmia and Ageusia

Cited by 51 publications

References 480 publications

Effect of natural products use prior to infection with COVID-19 on disease severity and hospitalization: A self-reported cross-sectional survey study

Effect of natural products use prior to infection with COVID-19 on disease severity and hospitalization: A self-reported cross-sectional survey study

Antiviral Effects of Some Flavonoids on SARS-CoV-2

Chemical Constituents of Essential Oils Used in Olfactory Training: Focus on COVID-19 Induced Olfactory Dysfunction

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