TABLE 1.
Characteristics of included studies.
| Herbal remedy | References | Plant species | Plant part | Preparation | Daily dose (mg) | Control | Concomitant treatment (both groups) | Patient type | Follow-up duration for measuring outcomes (weeks) | Study types included | Number of trials | Total number of participants |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Aloe vera | Suksomboon et al., (2016) | Aloe vera (L) Burm. F. (Xanthorrhoeaceae) | leaf | raw/juice/gel powder | 600–30,000 | Placebo/no treatment | OHA/insulin | T2DM | 8–12 | RCTs | 5 | 235 |
| Aloe vera | Zhang et al., (2016) | Aloe vera (L) Burm. F. (Xanthorrhoeaceae) | leaf | juice/powder | 200–2,800 | Placebo | None | T2DM + prediabetes | 6–12 | RCTs | 5 | 415 |
| Astragalus | Tian et al., (2016) | Astragalus membranaceus (Fisch) Bunge (Fabaceae) | root | aqueous decoction/injection | 1,200–320,000 | No treatment | OHA | T2DM | 2–16 | RCTs | 13 | 1,054 |
| Cinnamon | Allen et al., (2013) | Cinnamomum cassia (L.) J.Presl (Lauraceae) | Bark | aqueous extract/raw powder | 120–6,000 | Placebo | OHA | T2DM | 4–18 | RCTs | 10 | 464 |
| Cinnamon | Davis and Yokoyama, (2011) | Cinnamomum cassia (L.) J.Presl (Lauraceae) | Bark | powder/aqeuous extract | 250–6,000 | Placebo | OHA/none | T2DM + prediabetes | 4–16 | RCTs | 8 | 369 |
| Cinnamon | Deyno et al., (2019) | Cinnamomum cassia (L.) J.Presl and Cinnamomum verum J.Presl (Lauraceae) | NS | capsules | 1,000–14,400 | Placebo | OHA/none | T2DM + prediabetes | 4–16 | RCTs | 16 | 1,098 |
| Cinnamon | Leach and Kumar, (2012) | Cinnamomum cassia (L.) J.Presl and Cinnamomum burmanni (Nees & T.Nees) Blume (Lauraceae) | NS | tablet/capsule | 500–6,000 | Placebo | OHA/insulin | T1+T2DM | 4–16 | RCTs | 10 | 304 |
| Cinnamon | Namazi et al., (2019) | Cinnamomum cassia (L.) J.Presl (Lauraceae) | NS | Powder/extract | 120–6,000 | Placebo | None | T2DM | 6–17 | RCTs | 18 | 1,100 |
| Dragon Fruit | Poolsup et al., (2017) | Hylocereus polyrhizus (F.A.C.Weber) Britton & Rose; Hylocereus costaricensis (F.A.C.Weber) Britton & Rose (Cactaceae) | Fruit | Fresh fruit | 100,000–600,000 | No treatment | NS | T2DM | 2–4 | RCTs | 2 | 58 |
| Fenugreek | Neelakantan et al., (2014) | Trigonella foenum-graecum L (Fabaceae) | seed | powder/extract in capsules/chapati | 1,000–100,000 | Placebo | OHA | T2DM | 1.5–12 | 9 RCTs and 1 controlled trial | 10 | 278 |
| Gegen formulae | Yang et al., (2019) | Pueraria lobata (Willd.) Ohwi (Fabaceae) | Root | mixture | NS | Placebo | OHA/insulin | T2DM | 2–24 | RCTs | 13 | 1,440 |
| Ginger | Huang et al., (2019) | Zingiber officinale Roscoe (Zingiberaceae) | NS | NS | 1,600–4,000 | NS | NS | T2DM | 8–12 | RCTs | 8 | 454 |
| Ginseng | Gui et al., (2016) | Panax quinquefolius L and Panax ginseng C.A.Mey (Araliaceae) | NS | Raw herb/hydrolysed extract in capsules | 960–13,500 | Placebo | Nil | Untreated early diabetes + prediabetes | 4–20 | RCTs | 8 | 390 |
| Ginseng | Kim et al., (2011) | Panax ginseng C.A.Mey (Araliaceae) | Root | Red Ginseng powder/fermented powder | 780–3,000 | Placebo | OHA | T2DM | 12–24 | RCTs | 3 | 76 |
| Jinqi Jiangtang | Gao et al., (2019) | Astragalus membranaceus (Fisch) Bunge (Fabaceae); Coptis chinensis Franch. (Ranunculaceae); Lonicera japonica Thunb. (Caprifoliaceae) | Root (Astragalus and Coptis), Flower (Lonicera) | Tablets | 2,520–16,800 | No treatment | OHA | T2DM | 3–26 | RCTs | 17 | 1,365 |
| Momordica charantia | Ooi et al., (2012) | Momordica charantia L (Cucurbitaceae) | fruit | dried powder in capsules | 3,000 | Placebo, OHA | Diet only | T2DM | 12 | RCTs | 1 | 40 |
| Momordica charantia | Peter et al., (2019) | Momordica charantia L (Cucurbitaceae) | Fruit | dried pulp/juice | 1,200–6,000 | Placebo, OHA | OHA/none | T2DM | 4–16 | RCTs | 6 | 243 |
| Mulberry | Shin et al., (2016) | Morus alba L. (Moraceae) | leaf | Extract in capsules | 1,000 | Placebo, OHA | None | T2DM | 12 | RCTs | 1 | 23 |
| Nettle | Ziaei et al., (2020) | Urtica dioica L (Urticaceae) | NS | NS | 1,500–10,000 | placebo | None | T2DM | 8–12 | RCTs | 8 | 266 |
| Nigella sativa | Daryabeygi-Khotbehsara et al., (2017) | Nigella sativa L (Ranunculaceae) | seed | powder/oil | 500–2000mg; 1–5 ml | Placebo | OHA/none | T2DM | 8–52 | 4 RCTs and 3 non-randomised controlled trials | 7 | 505 |
| Olive Oil | Schwingshackl et al., (2017) | Olea europaea L. (Oleaceae) | fruit | oil | 10,000–75,000 | Low-fat diet/fish oils/PUFA | NS | T2DM | 2–208 | RCTs | 25 | 1724 |
| Psyllium Fiber | Gibb et al., (2015) | Plantago psyllium L.; Plantago ovata Forssk. (Plantaginaceae) | Seed | husk | 6,800–15,000 | Placebo/no treatment | None | T2DM | 6–12 | RCTs | 4 | 245 |
| Sweet Potato | Ooi and Loke, (2013) | Ipomoea batatas (L.) Lam. (Convolvulaceae) | Rhizome | Dry powder in tablets | 4,000 | Placebo | None | T2DM | 6–20 | RCTs | 2 | 122 |
| Tea | Li et al., (2016) | Camellia sinensis (L.) Kuntze (Theaceae) | Leaf | green/black/oolong tea/capsules | 150–1,500 | Placebo/water | NS | T2DM | 4–16 | RCTs | 12 | 658 |
| Tianmai Xiaoke | Gu et al., (2018) | Trichosanthes kirilowii Maxim. (Cucurbitaceae); Ophiopogon japonicus (Thunb.) Ker Gawl. (Asparagaceae); Schisandra chinensis (Turcz.) Baill. (Schisandraceae) | Root (Trichosanthes, Ophiopogon); Fruit (Schisandra) | Tablets, also containing chromium picolinate (1.6 mg per tablet) | 480 | No treatment | OHA/insulin | T2DM | 8–16 | RCTs | 7 | 717 |
Abbreviations: OHA, oral hypoglycaemic agent; T1DM, Type 1 Diabetes Mellitus; T2DM, type 2 diabetes mellitus; NS, Not Specified; RCTs, Randomised Controlled Trials.