Methods: Seeds of T. ammi were extracted using three different solvents n-hexane, chloroform, and methanol by using soxhlet apparatus. To assess the immunomodulatory effect, delayed-type hypersensitivity (DTH) assay method was used and by the DTH assay, the effect of T. ammi on the skin thickness of rats was estimated. To find the exact dose for administration, acute toxicity test was performed using crude methanolic extract at a dose of 400, 800, 1600, and 3200mg/kg. After acute toxicity test, 500mg/kg dose was determined as safe for therapeutic effect and immunomodulatory effect was evaluated at this dose. Dose of 500mg/kg was administered to Wistar rats daily for 14 days and skin thickness of rats was measured at 24, 48, and 72h.

Results: Results were obtained from six groups of rats, which were positive control group, negative control group, and the groups receiving the test drugs. Standard drug was the combination of sodium selenite, vitamin E, and sodium chloride and it showed more positive results as compared to that of test drug. Furthermore, among the three extracts, methanol extract showed more effectiveness on skin thickness.

Materials and Methods: Three different seed extracts were prepared through Soxhlet extraction method by using n-hexane, chloroform and methanol solvents. Acute toxicity test performed at dose of 400 mg/ kg, 800 mg/kg, 1600 mg/kg and 3200 mg/kg. Two different strengths of seed extracts (minimum therapeutic dose of 500 mg/kg and maximum therapeutic dose of 1000 mg/kg) were given to Wistar rats to measure anti-inflammatory activity through Carrageenan induced paw edema method.

Results: The standard drug diclofenac sodium was (percentage of inhibition of paw edema 29.68%) more effective as compared to test drug. When efficacy of all extracts compared with each other, n-hexane extract showed more anti-inflammatory effect (percentage inhibition of paw edema 22.21%) at maximum effective dose 1000 mg/kg.

Methods: The current study was cross-sectional population-based and used a convenient sampling technique. Moreover, Lorenz's formula was used to calculate the sample size and the required sample size was 480. Data were collected through face-to-face interviews with a pre-validated questionnaire and the study was conducted in Kuala Lumpur (Malaysia). Descriptive statistics, cross-tabulation, and logistic regression were executed by using SPSS version 24.

Results: Out of 480 participants, 45.8% were polled male and the prevalence of SMA in this study was found to be 15.1%. The majority of participants 23.1% indicated that they practiced antibiotics at least once in the last six months. The commonly self-medicated antibiotics were amoxicillin-clavulanate 20.6%, ampicillin/cloxacillin 14.2%, and levofloxacin 8.3%. Moreover, 64.8% of participants indicated that they bought their antibiotics from pharmacies. Whereas, most of the participants practice antibiotics to save money 19.2% and time 23.1%. Findings from multivariate logistic regressions showed that predictors of SMA were male gender, (95% CI: 0.300-0.877) occupation (95% CI: 0.122-10.797), health insurance (95% CI: 0.025-0.472), and education (95% CI: 0.084-0.800).

TRIAL DESIGN: The study is a randomized, placebo-controlled, adaptive clinical trial with parallel group design, superiority framework with an allocation ratio of 1:1 among experimental (HNS) and placebo group. An interim analysis will be done when half of the patients have been recruited to evaluate the need to adapt sample size, efficacy, and futility of the trial.

PARTICIPANTS: All asymptomatic patients with hospital or community based COVID-19 exposure will be screened if they have had 4 days exposure to a confirmed case. Non-pregnant adults with significant exposure level will be enrolled in the study High-risk exposure (<6 feet distance for >10min without face protection) Moderate exposure (<6 feet distance for >10min with face protection) Subjects with acute or chronic infection, COVID-19 vaccinated, and allergy to HNS will be excluded from the study. Recruitment will be done at Shaikh Zayed Post-Graduate Medical Institute, Ali Clinic and Doctors Lounge in Lahore (Pakistan).

INTERVENTION AND COMPARATOR: In this clinical study, patients will receive either raw natural honey (0.5 g) and encapsulated organic Nigella sativa seeds (40 mg) per kg body weight per day or empty capsule with and 30 ml of 5% dextrose water as a placebo for 14 days. Both the natural products will be certified for standardization by Government College University (Botany department). Furthermore, each patient will be given standard care therapy according to version 3.0 of the COVID-19 clinical management guidelines by the Ministry of National Health Services of Pakistan.

MAIN OUTCOMES: Primary outcome will be Incidence of COVID-19 cases within 14 days of randomisation. Secondary endpoints include incidence of COVID-19-related symptoms, hospitalizations, and deaths along with the severity of COVID-19-related symptoms till 14th day of randomization.

RANDOMISATION: Participants will be randomized into experimental and control groups (1:1 allocation ratio) via the lottery method. There will be stratification based on high risk and moderate risk exposure.

BLINDING (MASKING): Quadruple blinding will be ensured for the participants, care providers and outcome accessors. Data analysts will also be blinded to avoid conflict of interest. Site principal investigator will be responsible for ensuring masking.

NUMBERS TO BE RANDOMISED (SAMPLE SIZE): 1000 participants will be enrolled in the study with 1:1 allocation.

TRIAL STATUS: The final protocol version 1.4 was approved by institutional review board of Shaikh Zayed Post-Graduate Medical Complex on February 15, 2021. The trial recruitment was started on March 05, 2021, with a trial completion date of February 15, 2022.

TRIAL REGISTRATION: Clinical trial was registered on February 23, 2021, www.clinicaltrials.gov with registration ID NCT04767087 .