Black garlic extract is obtained from fresh garlic (Allium sativum) through a long fermentation process at controlled temperature and humidity. The transformation of constituents results in special bioactive compounds that differ in composition and effect from regular garlic.

Production and chemical transformation

Fresh garlic is fermentatively aged for 3–6 weeks at 60–90 °C and 70–90% humidity. Maillard reactions occur during this process, lowering the pH and coloring the white cloves a deep black. Allicin decomposes almost completely during this process; at the same time, stable, water-soluble sulfur compounds such as S-allyl-cysteine ​​(SAC) are formed. as well as phenolic antioxidants and melanoidins.

Key active ingredients

Connection	Structure/Source	Main functions	Special features
Alliin (S-allyl-L-cysteine ​​sulfoxide)	naturally in intact garlic	stable, odorless pro-molecule	Substrate of alliinase; starting point for allicin
Allicin (Diallyl thiosulfinate)	arises from alliin after cell injury	strong antimicrobial, short-lived radical scavenger	unstable, irritating; &<0.1% in black garlic
S-allyl-cysteine ​​(SAC)	formed from allicin during aging	antioxidant, anti-inflammatory, H₂S and NO modulator	high oral bioavailabilityüavailability (≈ 98%)

Therapeutic areas of application – clinical evidence

cardiovascular system

A triple-blind RCT with 81 patients with stage I hypertension investigated 250 mg of a standardized black garlic extract (ABG10⁺, 0.25 mg SAC) üover 12 weeks. Systolic and diastolic blood pressure decreased by 1.8 mmHg and 1.5 mmHg, respectively, compared to placebo; at the same time, plasma NO and total antioxidant capacity increased, while ACE activity and uric acid decreased.. Tolerability was excellent.

Lipid metabolism

In a double-blind RCT with 60 subjects with mild hypercholesterolemia, a 12-week supplementation of 6 g aged black garlic/day HDL cholesterol significantly and reduced apolipoprotein B and the LDL-C/ApoB ratio, without relevant side effects. Animal studies confirm the lipid-lowering effect through down-regulation of SREBP-1c, ACC and HMG-CoA reductase.

Glycemic control

Preclinical work on diabetic Wistar rats showed that 25 days of black garlic extract reduced fasting blood sugar by ≈ 90% and LDL-C by > 80% reducedHuman studies on glucose control are pending.

Neuroprotection

SAC behaved in vitro as a H₂S donor, stimulated eNOS phosphorylation and reduced ROS load in endothelial cellsIn rat models, black garlic extract prevented both acrylamide-induced neuronal apoptosis and MSG-induced working memory deficits.

Anti-inflammatory and antioxidant cell protection

Several in vitro- and animal studies demonstrate a Inhibition of NF-κB, COX-2, iNOS, TNF-α and IL-6 by SAC-rich fractionsAt the same time, endogenous antioxidants (SOD, GSH-Px) increase. These effects underpin the cardioprotective and potentially chemopreventive properties.

Overview of human studies on black garlic extract

Indication/Subjects	Preparation (SAC content)	Length of time	Main result
Stage I hypertension (n = 81)	250 mg ABG10⁺ (0.25 mg SAC)	12 weeks	SBP − 1.8 mmHg; DBP − 1.5 mmHg; ↑NO; ↓ACE
Mild hypercholesterolemia (n = 55)	2 × 3 g aged BG (SAC ≙ ≈1 mg)	12 weeks	↑HDL-C (+5%), ↓ApoB (−7%)

SBP = systolic, DBP = diastolic blood pressure; all changes vs. placebo.

Pharmacological mechanisms

1. Antioxidant potency: SAC, polyphenols and melanoidins neutralize free radicals and reactivate endogenous defense systems (SOD, CAT).
2. Gasotransmitter modulation (d.h. Regulation of the activity of gastrotransmitters – these are small, gaseous molecules involved in cell communication): SAC releases H₂S, increases eNOS activity and increases NO bioavailability – which explains the positive vasodilatory effects (dilation of blood vessels).
3. Renin-angiotensin system: Inhibition of ACE activity contributes to lowering blood pressure.
4. Lipid metabolism: Inhibition of SREBP-1c-dependent lipogenesis steps and HMG-CoA reductase reduces TG and cholesterol.
5. NF-κB blockade: Sulfur-containing compounds dampen pro-inflammatory signaling pathways.

Dosage, safety and tolerability

Clinical studies used daily doses between 250 mg and 600 mg standardized extract (≈ 0.25-0.6 mg SAC) and 6 g non-standardized aged black garlicOdor and stomach irritation are avoided due to the degradation of allicin; interactions with anticoagulants have not been reported to date.

Conclusion

Black garlic extract offers a high concentration of the stable active ingredient S-allyl-cysteine and other organic sulfur metabolites clinically proven potential for blood pressure and lipid controlPreclinical data suggest additional neuroprotective and antidiabetic benefits.

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