Spices have a long history of being used to enhance the flavour of food and as folk medicines for thousands of years.
Spices typically come from the dried part of a plant such as buds, flowers (cloves, saffron); bark (cinnamon); root (ginger, turmeric); fruits/berries (cloves, chili, black pepper); or seeds (cumin) that contain volatile oils or aromatic scents and flavors. 
Spices have been reported to have various beneficial effects on human health which include anti-sclerotic, antithrombotic, anti-carcinogenic, anti-inflammatory, antiarrhythmic, anti-rheumatic, gastroprotective, and lipid-lowering action.
In addition, spices have radioprotective (protects against radiation), anti-allergic, and antimalarial effects. Spices inhibit the oxidation of low-density lipoprotein and protein glycation. 
In this article we are going to take a look at some of the evidence-based health benefits of common spices.
Spices have a long traditional history of being used to treat infectious diseases, due to their broad-spectrum antiseptic and antimicrobial properties.
Modern clinical research has also shown that many spices such as cloves, cinnamon, cumin and turmeric to possess significant antibacterial and antifungal activities.
Spices have shown to be effective against a number of pathogens from food-spoilage bacteria to even antibiotic resistant microorganisms such as methicillin resistant Staphylococcus aureus. 
The antimicrobial activity of spices is thought to be largely attributed to the essential oil fraction.
Spices have long been used as food preservatives due to their potent antimicrobial properties, which help to suppress harmful food-borne pathogens.
Spices are amongst the plant-foods which are the richest dietary sources of antioxidants and high in phenolic compounds.
The bioactive compounds present in spices having antioxidant properties mainly consists of flavonoids, phenolic compounds, sulfur-containing compounds, tannins, alkaloids, phenolic diterpenes, and vitamins. 
Research has found Cloves to have the most potent antioxidant capacity of all the spices.
Followed by allspice(fruits of Pimenta dioica) and Cinnamon(bark of Cinnamomum verum). 
Other spices which have shown antioxidant activity include Cardamom, Cumin, Ginger, Nutmeg, Saffron and Turmeric.
3. Anti-Depressant Properties
A number of spices such as Saffron and Turmeric now have a growing body of scientific evidence on their potential anti-depressant properties.
The spice Saffron in particular has shown in many clinical trials to improve symptoms of MDD (Major Depressive Disorder)
Saffron exerts its anti-depressant effect through numerous potential mechanisms such as increasing levels of the neurotransmitter serotonin, antioxidant, anti-inflammatory and neuroprotective properties.
Inflammation, oxidative and nitrosative stress appear to play key roles in the pathophysiology of depression.
Potent antioxidant and anti-inflammatory spices such as Saffron and Curcumin from Turmeric may hold huge potential for attenuating these pathways.
Check out our previous article which includes some of the latest systematic reviews and meta-analysis on Saffron’s anti-depressant benefits at: Saffron & Depression
Turmeric root has a long history of being used in Ayurvedic medicine to treat anxiety and depression.
Research also suggests that Curcumin the main active component of the spice Turmeric may be of benefit for depression due to its diverse biological activities.
Curcumin has displayed, in a number of studies, a potency in modulating neurotransmitter concentrations, inflammatory pathways, excitotoxicity, neuroplasticity, hypothalamic–pituitary–adrenal disturbances, insulin resistance, oxidative and nitrosative stress, and endocannabinoid system, all of which can be involved in MDD pathophysiology. 
Recommended Curcumin Supplement: Micellar Curcumin – YourZooki
Spices may be some of the most potent functional foods that one can include in a plant-based diet to prevent the development of cancer.
Spices contain a diverse range of bioactive phytochemicals with chemopreventive and chemotherapeutic potential properties.
The main mechanisms of action include inducing apoptosis, inhibiting proliferation, migration and invasion of tumors, and sensitizing tumors to radiotherapy and chemotherapy. 
Some of the Spices which have shown anti-cancer and anti-tumor effects include Black Cumin, Black Pepper, Cardamom, Clove, Ginger, Red Chili Pepper, Saffron and Turmeric/Curcumin.
Spices such as Turmeric and their principal components such as Curcumin have exhibited potent anti-inflammatory activity in studies and the ability to modify dysregulated inflammatory pathways through a variety of mechanisms.
It is now well established that chronic low-grade systemic inflammation plays a vital role in the development of many common chronic diseases such as cardiovascular disease.
Many spices have exhibited anti-inflammatory properties including Black Pepper(Piperine), Cinnamon, Cumin, Ginger, Red Chili Pepper (Capsicum) and Saffron.
The information in this article has not been evaluated by the FDA and should not be used to diagnose, cure or treat any disease, implied or otherwise.
Always consult with a qualified healthcare professional before making any significant dietary or lifestyle changes including supplements and herbs.