###### Abstract
In the case of structural compounds, the direct interaction of the metallodrug, in its original structure, with the biotarget is responsible for the therapeutic effect. Conversely, in the case of functional compounds, also known as prodrugs, the metal complex is not supposed to interact directly with the biotarget. More in detail, the metal complex undergoes modifications in the biological environment with respect to its original structure (e.g., release of one or more ligands), and only in this form it can interact with the main biotarget. In addition to their functional or structural behaviour, metal-based compounds can act as: (i) carriers for active ligands, (ii) catalysts or (iii) photoactivable species [15]. More recently, the classification of metallodrugs has been improved by adding more detailed classes such as: (i) bioconjugated metallodrugs, (ii) inhibitors of enzymes via substrate and metabolite mimics, (iii) redox-active derivatives [16], (iv) photoactivable compounds for photodynamic and photoactivated therapies [17; 18; 19; 20], (v) metal complexes for delivery and release of pharmacologically active ligands, (vi) catalytic drugs [20; 21], (vii) radiometals and radioactive agents for radio-imaging and radiotherapy [20; 21] and (viii) magnetic resonance imaging (MRI) contrast agents [22]. In this vast scenario, some authors preferred to classify metal-based complexes of biological interest based on the type of metal centre, therapeutic effect and reactivity/stability in biological media [23; 24; 25; 26; 27; 28; 29; 30]. In all these contributions, the design of heterobimetallic complexes and the conjugation of metal complexes to a bioinspired target moiety seem the most promising strategies to boost the efficacy of biologically active metal derivatives [31; 32; 33]. In particular, the new generations of metallodrugs are usually characterized by the presence of natural derivatives directly anchored to the metal centre and/or to the ancillary ligands [34]. The presence of a natural moiety is aimed at improving the biocompatibility of metallodrugs, thus reducing their side-effects and facilitating the drug delivery. It should be remembered that with the term \"natural\", we can consider all molecules that derive from living organisms present in nature. In this context, the most interesting bioconjugated metallodrugs contain plant derivatives such as coumarins and xanthines (e.g., caffeine) [35; 36; 37; 38; 39; 40; 41], food derivatives (e.g., polyphenols) [39; 42] and classical biomolecules of life. Within this context, in 2019, [PERSON] and [PERSON] assembled a review dealing with metal complexes conjugated to natural products for cancer therapy [43]. In the same year, [PERSON], [PERSON] and [PERSON] fixed the state of the art of metal complexes with natural products from different biosynthetic pathways such as terpen, curcumins, coumarins, steroids, naphto- and anthraquinones and tetracyclines [44]. Herein, we propose an overview of the recent advances in this vast area of research, with a special focus on metal-based anticancer agents bearing the essential biomolecules of life: carbohydrates, amino acids and proteins, lipids (steroid and hormones), nucleic acids and vitamins. For convenience, abbreviations for the cell lines and tumour types cited in the main text are reported in the final Appendix A.